Note: Descriptions are shown in the official language in which they were submitted.
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
ANTIMICROBIAL ARTICLES AND METHOD OF MANUFACTURE
The present invention relates to antimicrobial articles comprising silver and
to
methods for the manufacture of such articles.
Background
While skin wounds heal more effectively in moist environments, the risk of a
bacterial infection increases in the presence of moisture. Moreover, bacteria
can build a
resistance to antibiotics, eventually rendering an antibiotic ineffective.
Silver compounds
are known to impart antimicrobial effects to a surface (e.g., wound tissue)
with minimal
risk of developing bacterial resistance. In the moist environment of a wound
bed, for
example, silver is delivered by the sustained release of silver ions into the
wound.
The literature has reported that silver salts coated on cotton or other
substrates, in
the absence of stabilizers, are not color stable upon exposure to ultraviolet
("UV") or
visible light. However, stabilizers also reduce the solubility of the silver
salts which also
inhibits the release of silver ions. If the release of silver ions is too low
(less than 0.01
mg/g dressing in water in 30 minutes) its antimicrobial action will also be
reduced and it
may no longer be efficacious for the treatment of a wound.
It is desirable to provide color stable antimicrobial articles and methods for
the
manufacture of such articles wherein the articles provide antimicrobial
activity when used
as wound dressings or the like.
Summary
The present invention provides articles and methods for the manufacture of
such
articles.
In an aspect of the invention, a method of making an antimicrobial article is
provided, the method comprising: applying a silver composition to a substrate
to provide a
liquid coated substrate, the silver composition comprising a silver salt other
than silver
sulfate in a solvent, the silver composition comprising stabilizing agent in
an amount less
than about 100 parts per million (ppm); the substrate comprising material
selected from
the group consisting of polyamide, polyester, polyacetate, polyacrylic,
polyolefin,
1
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
polyurethane, polyvinylchloride, polyvinyl alcohol, polycarbonate,
polyvinylpyrrolidone,
polylactic acid, ethylene-vinyl acetate, polystyrene, cellulose acetate,
polyacrylate,
polyacrylamide, polyacrylonitrile, polyvinylidene difluoride,
polytetrafluoroethylene,
polyoxymethylene, polyvinyl ether, styrene-ethylenebutylene-styrene elastomer,
styrene-
butylene-styrene elastomer, styrene-isoprene-styrene elastomer, glass fiber,
ceramic and
combinations of two or more of the foregoing; and drying the liquid coated
substrate to
provide a color stable antimicrobial article comprising silver salt applied to
the substrate.
In another aspect, the invention provides an article, comprising: a silver
salt other
than silver sulfate, the silver salt applied to a substrate; and the substrate
comprising
material selected from the group consisting of polyamide, polyester,
polyacetate,
polyacrylic, polyolefin, polyurethane, polyvinylchloride, polyvinyl alcohol,
polycarbonate,
polyvinylpyrrolidone, polylactic acid, ethylene-vinyl acetate, polystyrene,
cellulose
acetate, polyacrylate, polyacrylamide, polyacrylonitrile, polyvinylidene
difluoride,
polytetrafluoroethylene, polyoxymethylene, polyvinyl ether, styrene-
ethylenebutylene-
styrene elastomer, styrene-butylene-styrene elastomer, styrene-isoprene-
styrene elastomer,
glass fiber, ceramic and combinations of two or more of the foregoing; and
wherein the
article is antimicrobial and color stable.
In another aspect of the invention, a method is provided, comprising: applying
a
silver composition to a substrate to provide a liquid coated substrate, the
silver
composition comprising a silver salt selected from the group consisting of
silver acetate,
silver benzoate, silver carbonate, silver chloride, silver citrate, silver
iodate, silver lactate,
silver nitrate, silver nitrite, silver oxalate, silver phosphate, silver
sulfadiazine, silver
saccharinate, silver anthranilate, silver chlorite, silver fluosilicate,
silver trihydrogen
paraperiodate, silver hyponitrite, silver levunilate, silver myristate, silver
palmitate, silver
propionate, silver stearate, silver tartrate, mild silver protein, silver
protein and
combinations of two or more of the foregoing; and heating the liquid coated
substrate at a
temperature sufficient to form silver metal from silver salt to provide a
color stable
antimicrobial article comprising silver metal nanoparticles and silver salt.
In another aspect, the invention provides a method of making an antimicrobial
article, comprising: applying a silver composition to a substrate to provide a
liquid coated
substrate, the silver composition comprising a silver salt other than silver
sulfate; and
heating the liquid coated substrate at a temperature sufficient to form silver
metal from
2
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
silver salt to provide a color stable antimicrobial article comprising silver
metal
nanoparticles and silver salt.
In still another aspect, the invention provides an article, comprising: a
silver metal
and silver salt disposed on a substrate, the silver salt selected from the
group consisting of
silver acetate, silver benzoate, silver carbonate, silver chloride, silver
citrate, silver iodate,
silver lactate, silver nitrate, silver nitrite, silver oxalate, silver
phosphate, silver
sulfadiazine, silver saccharinate, silver anthranilate, silver chlorite,
silver fluosilicate,
silver trihydrogen paraperiodate, silver hyponitrite, silver levunilate,
silver myristate,
silver palmitate, silver propionate, silver stearate, silver tartrate, mild
silver protein, silver
protein and combinations of two or more of the foregoing.
In still another aspect, the invention provides an article, comprising: a
silver metal
and silver salt applied to a substrate, the silver salt comprising a silver
salt other than silver
sulfate.
The terminology used herein will be understood to have the same meaning as
understood by those skilled in the art. Notwithstanding the foregoing
statement, certain
terms shall be understood to have the meaning set forth herein.
As used herein, "Ambient temperature" means the existing room temperature,
typically within a range from about 15 C to about 30 C.
"Relative humidity" means the ratio of the amount of water vapor actually
present
in the air to the greatest amount possible at the same temperature.
As used herein, "a," "an," "the," "at least one," and "one or more" are used
interchangeably.
Those skilled in the art will more fully appreciate the scope of the present
invention upon consideration of the remainder of the disclosure, including the
Detailed
Description Of Embodiments Of The Invention, the various Examples and the
appended
claims.
Detailed Description Of Embodiments Of The Invention
The present invention provides antimicrobial articles that contain silver. The
articles are color stable (when exposed to UV or visible light), release
antimicrobial levels
of silver ions, are surprisingly easy to manufacture and can be made into
wound dressings,
wound packing materials, or other material suitable for application directly
on a wound.
3
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
In describing the embodiments of the invention, the term "color stable" means
that
the article does not exhibit a significant observable change in color and/or
homogeneity of
color over time (e.g., for at least 4 hours after exposure to light). Color
change can be
evaluated in any of a variety of ways, and the present invention is not
limited to a
particular method or technique to determine color change.
In some embodiments of the invention, color change is evaluated by
observation.
In some embodiments, color change is evaluated using a graduated scale. For
example, color change may be evaluated by observing a sample under fluorescent
lighting
and assigning a rating from 0 to 10 to the color of the sample by comparing it
to color
standards. A rating of 0, 1 or 2 is considered to be "white" including white
to cream. A
rating from 3 through 5 is "yellow" including light yellow to golden yellow,
and a rating
from 6 through 10 is classified as rust to dark brown. A numerical value for
color change
is obtained by obtained by subtracting the initial rating from the rating
after treatment.
Positive ratings for color change represent a darkening in appearance and
negative ratings
represent a lightening in appearance. A color change on this scale of 1 or
less is
considered acceptable (e.g., no significant change) as long as the color is
initially
homogeneous and remains so. If the color is initially non-homogeneous, a color
change of
0.5 is considered significant.
In some embodiments, color change can also be measured using a colorimeter
such
as a Minolta Chroma Meter (CR-300, manufactured by Konica Minolta Photo
Imaging
U.S.A., Inc., Mahwah, NJ) using tristimulus values. A color change on this
scale in the
"Y" value of 15% or less is considered to be acceptable as long as the color
of the sample
remains homogeneous. If the color is non-homogeneous, a color change of 5% in
the "Y"
value is considered a significant.
In still other embodiments, color change can be measured using a colorimeter
according to test method ASTM D2244. The resulting CIELAB color difference
(DE*),
between the sample after exposure for the indicated period of time and the
unexposed
sample can be determined. For purposes of reference only, a DE*, or color
change of
about 2 units is considered to be the threshold for detection by the naked eye
whereas a
DE* of 20 or greater represents a substantial or significant color change.
Typically, the art has relied on the use of chemical compounds known as
stabilizers to provide color stability to articles that include silver salt.
But, such stabilizers
4
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
can also reduce the solubility of silver salts so that the release of silver
ions can be too low
(less than 0.01 mg/g dressing in water in 30 minutes) to be efficacious for a
wound.
In one embodiment of the present invention, color stability is achieved by
applying
a silver composition onto a substrate and drying the article. When an
appropriate substrate
is used to make the articles of the invention, the dried article is color
stable without the
need to include stabilizers or the like.
In another embodiment of the present invention, color stability is achieved by
reducing a portion of silver salt (preferably less than 30%) applied to a
substrate to nano-
scale silver metal particles ("nanoparticles") via drying at an elevated
temperature to
create a product that is color stable with a color that is often observed as
light yellow to
golden brown as a result of the formation of silver metal nanoparticles.
In one aspect of the invention, a method is provided for making antimicrobial
articles by applying (e.g., coating) silver compound(s) onto a substrate to
provide a color
stable antimicrobial article comprising silver salt.
In another aspect of the invention, a method is provided for making
antimicrobial
articles by applying (e.g., coating) silver compound(s) onto a substrate to
provide a color
stable antimicrobial article comprising silver metal and silver salt.
In some embodiments, a silver composition is first prepared by dissolving
silver
salt in a suitable solvent (e.g., water) to provide a coatable liquid silver
composition in the
form of a silver salt solution. In some embodiments, the solvent used in the
silver
composition consists of water. In some embodiments, the solvent in the silver
composition is predominantly water along with other ingredients that enhance
the
solubility of the silver salt. Silver salts suitable for use in the present
invention can be
selected from the group consisting of silver acetate, silver benzoate, silver
carbonate,
silver chloride, silver citrate, silver iodate, silver lactate, silver
nitrate, silver nitrite, silver
oxalate, silver phosphate, silver sulfadiazine, silver saccharinate, silver
anthranilate, silver
chlorite, silver fluosilicate, silver trihydrogen paraperiodate, silver
hyponitrite, silver
levunilate, silver myristate, silver palmitate, silver propionate, silver
stearate, silver
tartrate, mild silver protein, silver protein and combinations of two or more
of the
foregoing.
5
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
In certain embodiments, any one of the foregoing salts is suitable by itself
or in
combination with any other silver salt. Silver sulfate is not included with
the foregoing
salts.
In some embodiments, the silver salt is selected from a subset of the
foregoing salts
consisting of silver acetate, silver benzoate, silver carbonate, silver
chloride, silver citrate,
silver lactate, silver nitrate, silver nitrite, silver chlorite, silver
fluosilicate, silver
trihydrogen paraperiodate, silver levunilate, silver propionate, silver
tartrate, mild silver
protein, silver protein and combinations of two or more of the foregoing.
In some embodiments, the silver salt is selected from another subset of the
salts
consisting of silver iodate, silver oxalate, silver phosphate, silver
sulfadiazine, silver
saccharinate, silver anthranilate, silver hyponitrite, silver myristate,
silver palmitate, silver
stearate and combinations of two or more of the foregoing.
In some embodiments, the silver salt is selected to exclude silver sulfate. In
some
embodiments, the silver salt is silver nitrate. In some embodiments, the salt
is silver
benzoate.
The silver composition may be formulated with a total silver content of up to
about
1.0% by weight, typically between about 0.01% and about 0.5% by weight in the
composition. In some embodiments, the pH of the silver composition is
maintained at a
desired target value in order to avoid adverse effects to the substrate when
the composition
is applied thereto. In some embodiments, the pH of the silver composition is
maintained
at 9 or less. In some embodiments, the pH of the silver composition is
maintained above 4
but less than 7, to minimize adverse effects to cellulosic substrates, for
example.
Color stability is achieved in the finished articles of the invention without
the need
to include added stabilizing agent(s) to the silver composition; however, it
will be
appreciated that, in some embodiments of the invention, small amounts of
stabilizing
agent(s) may be included in the silver composition. Stabilizing agents include
ammonia,
ammonium salts (e.g., ammonium acetate, ammonium sulfate, ammonium carbonate
and
the like), thiosulfates, water insoluble salts of metals (e.g., halides such
as chlorides),
peroxides, magnesium trisilicate, and/or polymers. Stabilizing agents, when
present in the
silver composition, may be present in amounts less than 100 ppm. In some
embodiments,
stabilizers may be present in amounts less than 50 ppm, and in some
embodiments less
than 20 ppm, based on the total weight of the silver salt composition.
Alternatively,
6
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
stabilizing agents are present in amounts less than 1000 ppm based on the
total weight of
the dried color stable antimicrobial article. In still other embodiments,
stabilizing agents
are present in amounts less than 500 ppm based on the total weight of the
dried color
stable antimicrobial article, and in still other embodiments stabilizing
agents are present in
amounts less than 100 ppm, based on the total weight of the dried color stable
antimicrobial article.
In some embodiments, the silver composition may optionally include compounds
to facilitate solubility of the silver salt in the solvent (e.g., water).
Depending on the
solubility of the salt(s) selected for use in the present invention,
embodiments of the
invention may include solubilizing agents selected from the group consisting
of
ammonium pentaborate, ammonium acetate, ammonium carbonate, ammonium
peroxyborate, ammonium tertraborate, triammonium citrate, ammonium carbamate,
ammonium bicarbonate, ammonium malate, ammonium nitrate, ammonium nitrite,
ammonium succinate, ammonium sulfate, ammonium tartarate, and combinations of
two
or more of the foregoing. In the selected of solubilizing agents for inclusion
in the silver
composition of the invention, preference is given to substances that will
evaporate or
degrade following application of the composition on a substrate and heating as
described
herein.
The thus formulated silver composition is applied to a substrate to provide a
liquid
coated substrate. In some embodiments, the silver composition will penetrate
and
impregnate the interior of the substrate. For example, when absorbent
materials (e.g.,
gauze), the silver composition impregnates between the fibers of the
substrate.
Application of the silver composition to a substrate can be accomplished as a
continuous
process, or it can be done in a discrete manner and even in a single step.
Any of a variety of materials may be used as a substrate or substrate material
to
which the silver composition is applied.
In certain embodiments, suitable materials can include polymeric materials or
is
comprised of large, long chain molecules. In certain embodiments, the material
for the
substrate is typically selected to be `non-oxidizable' in that it does not
readily oxidize in
the presence of silver salts (e.g., silver nitrate) when heated to
temperatures below about
120 C. Suitable substrates include materials selected from the group
comprising or
consisting of polyamide, polyester, polyacetate, polyacrylic, polyolefins
(e.g.,
7
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
polypropylene polyethylene, ethylene propylene copolymers, and ethylene
butylene
copolymers), polyurethanes (including polyurethane foams), polyvinylchloride,
polyvinyl
alcohol, polycarbonate, polyvinylpyrrolidone, polylactic acid, ethylene-vinyl
acetate,
polystyrenes, cellulose acetate, polyacrylate, polyacrylamide,
polyacrylonitrile,
polyvinylidene difluoride, polytetrafluoroethylene, polyoxymethylene,
polyvinyl ether,
styrene-ethylenebutylene-styrene elastomer, styrene-butylene-styrene
elastomer, styrene-
isoprene-styrene elastomer, glass fiber, ceramics and combinations of two or
more of the
foregoing.
In some embodiments of the invention, the substrate comprises or consists of
cellulose acetate. In some embodiments, the substrate comprises or consists of
polyamide
(e.g., Nylon 6, 6).
In certain embodiments, suitable materials can include cellulosic and non-
cellulosic materials such as, for example, paper, natural or synthetic fibers,
threads and
yarns made from materials such as cotton, rayon, hemp, jute, bamboo fibers,
cellulose
acetate, carboxymethylated solvent-spun cellulose fibers, polyamides,
polyacetates,
alginates, collagen, gelatin, natural rubber, polyacrylamide, and combinations
of two or
more of the foregoing.
In addition, the above material or combinations thereof can be combined with
other
materials such as polyesters, polyacrylics, polyolefins (e.g., polypropylene
polyethylene,
ethylene propylene copolymers, and ethylene butylene copolymers),
polyurethanes
(including polyurethane foams), vinyls including polyvinylchloride,
polystyrenes,
fiberglass, ceramic fibers, polyacrylate, polyacrylonitrile, polyvinylidene
difluoride,
polytetrafluoroethylene, polyoxymethylene, polyvinyl alcohol, polylactic acid,
polyvinyl
ether, polyvinylpyrrolidone, polycarbonate, styrene-ethylenebutylene-styrene
elastomer,
styrene-butylene-styrene elastomer, styrene-isoprene-styrene elastomer, and
combinations
of two or more of the foregoing. Combinations of materials may be included
within a
substrate. In some embodiments, the substrate comprises a material selected
from the
group consisting of cellulosic material, nylon, polyester fiber, and
combinations of two or
more of the foregoing.
The substrate can be porous or nonporous, and the silver composition can be
coated onto a surface of the substrate or impregnated into it, for example. In
embodiments
of the invention, the substrate may be flexible and can comprise woven or
nonwoven
8
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
materials made of natural or synthetic compounds. In embodiments of the
invention, the
substrate may be selected from polymeric webs (non-woven or woven), polymer
films,
hydrocolloids, foams, paper, and/or combinations of the foregoing.
In some embodiments, the substrate can be an absorbent cotton gauze.
Porous substrates made from the foregoing materials can include knits, wovens
(e.g., cheese cloth and gauze), nonwovens (including spun-bonded nonwovens,
and BMF
(blown micro fibers), extruded porous sheets, and perforated sheets. The
apertures (i.e.,
openings) in the porous substrates are of sufficient size and sufficient
number to facilitate
high breathability. For certain embodiments, the porous substrates have at
least 1 aperture
per square centimeter. For certain embodiments, the porous substrates have no
greater
than 225 apertures per square centimeter. For certain embodiments, the
apertures have an
average opening size (i.e., the largest dimension of the opening) of at least
0.1 millimeter
(mm). For certain embodiments, the apertures have an average opening size
(i.e., the
largest dimension of the opening) of no greater than 0.5 centimeter (cm). In
some
embodiments, the porous substrates have a basis weight of at least 5
grams/meter2. In
some embodiments, the porous substrates have a basis weight of no greater than
1000
grams/meter2 , and in some embodiments no greater than 200 grams/meter2.
Porous
substrates may be flexible yet resistant to tearing. For some embodiments, the
thickness
of the porous substrates is at least about 0.0125 millimeter (mm). For certain
embodiments, the thickness of the porous substrates is no greater than about
15 mm, and
for certain embodiments no greater than about 3 mm.
In some embodiments, the substrate comprises permeable material(s) that allow
for
moisture vapor transmission therethrough. For some embodiments, the substrate
may be a
hydrocolloid, such as a hydrophilic polymer, or hydrophobic polymer matrix
containing
hydrophilic particles, as described in U.S. Pat. App. Pub. Nos. 2004/0180093
and
2005/0124724.
Cellulosic materials may be suitable for use in certain embodiments of the
invention, including polysaccharide or modified polysaccharide, regenerated
cellulose
(such as rayon), paper, cotton, carboxymethyl cellulose, and the like. In
embodiments of
the invention where the finished article is intended for use as a wound
dressing or will be
used in a moist or wet environment, it may be advantageous to provide a
substrate
comprising absorbent materials. Suitable absorbent materials include those
made from or
9
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
incorporating cellulose fibers such as carboxymethylated materials -
carboxymethylated
cotton, carboxymethylated cellulose, carboxymethylated rayon. Suitable
commercial
cellulosic fibers include solvent-spun cellulosic fibers known under the trade
designation
"TENCEL" available from Lenzing Fibers, Inc. Carboxymethylated variations of
the
foregoing TENCEL fibers, as disclosed in W01993012275 A1, are also suitable
for use in
certain embodiments of the invention.
In some embodiments, the substrates are substantially impervious to liquid,
especially wound exudate.
The silver composition can be applied at ambient temperatures, typically at
temperatures less than about 70 C. The silver composition can be coated onto a
substrate
using any of a variety of known coating techniques such as gravure coating,
curtain
coating, die coating, knife coating, roll coating, spray coating and the like.
In some
embodiments, the substrate can be dipped into or passed through a bath of the
silver
composition.
Following the application of silver salt, moderate heat may be applied to the
liquid
coated substrate at a temperature and for a duration sufficient to dry the
article to provide a
color stable antimicrobial article. Sufficiently elevated temperatures may be
attained in an
oven and, in certain embodiments of the invention, the temperature is less
than 100 C and
typically within the range from about 50 C to about 90 C. Alternatively, the
liquid coated
substrate may be air dried at ambient or room temperature. Actual drying
temperatures
may vary depending on the amount of time allotted for drying, the silver
loading on the
liquid coated substrate, the type and weight of the substrate and the like.
Those skilled in
the art will appreciate that the temperature should be high enough to dry the
article without
reducing the silver salt or oxidizing the substrate. In this manner, the dried
article is color
stable. Not wishing to be bound by theory, it is believed that the articles of
the invention
produced in this manner are color stable due in part to the non-oxidizable
substrate(s)
being used. For some embodiments of this invention, the drying temperature can
by
higher than 100 C as long as the substrate is not oxidized by silver nitrate
to form silver
metal or the substrate does not melt or burn. Polyester is an example of this
type of
substrate.
In certain embodiments, heat is applied to the liquid coated substrate at a
temperature and for a duration sufficient to dry the article (by removing the
solvent from
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
the silver composition) and to reduce at least a portion of the silver salt to
silver metal to
provide a color stable antimicrobial article. At least a portion of the silver
metal is in the
form of nanoparticles of silver. As used herein, "nanoparticle" refers to a
microscopic
particle whose size is measured in nanometers (nm) having at least one
dimension less
than about 200 nm. To accomplish the formation of silver metal, the drying
temperature
for the liquid coated substrate is elevated above room temperature.
Sufficiently elevated
temperatures are attained in an oven and, in certain embodiments of the
invention, the
temperature is in excess of about 95 C and within the range from about 95 C to
about
225 C. In some embodiments, the liquid coated substrate is dried at
temperatures between
about 100 C and about 200 C. In still other embodiments, the liquid coated
substrate is
dried at temperatures between about 110 C and about 180 C. In still other
embodiments,
the liquid coated substrate is dried at temperatures between about 130 C and
about 175 C.
Actual drying temperatures may vary depending on the amount of time allotted
for drying,
the silver loading on the liquid coated substrate, the type and weight of the
substrate and
the like. Those skilled in the art will appreciate that the temperature should
be high
enough to achieve the reduction of silver (I), in embodiments where desired.
But,
consideration must also be given to the melting temperature and oxidation
potential of the
substrate. Those skilled in the art will appreciate that substrate materials
suitable for use
as wound dressings, for example, may comprise materials that are readily
oxidizable at
higher temperatures (e.g., cellulosic materials) so that prolonged heating or
exposure to
very high temperatures may be detrimental to the quality and/or the integrity
of the
finished article. An excessively high drying temperature can burn or melt some
substrate
materials and render them unfit for their intended purpose (e.g., as a wound
dressing).
In certain embodiments, the finished article includes silver metal and silver
salt
affixed to a substrate. Not wishing to be bound by any theory, it is believed
that the
heating of the liquid coated substrate in certain embodiments oxidizes the
substrate and
reduces the silver salt to silver metal. Oxidation of the substrate and
formation of
nanoparticles of metallic silver are believed to be responsible for the
color(s) and the color
stability observed in certain of the finished antimicrobial articles of the
invention. On
white substrates (e.g., cellulosic materials), heat treating the liquid coated
substrate can
result in a finished article having a non-white color (e.g., yellow to brown)
that is stable
for extended periods of time after exposure to light and/or heat.
11
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
Preferably, the articles of the invention remain stable to light (e.g.,
visible, UV)
such that they are color stable. Preferably, they release antimicrobially
efficacious levels
of silver ions and, in certain embodiments of the invention, are readily
applicable to skin
wounds as a wound dressing. The articles are simple to manufacture, and are
generally
free of added stabilizers.
In certain embodiments, the present invention provides a wound dressing that
comprises readily soluble silver salt(s) applied to a substrate. In other
embodiments, the
present invention provides a wound dressing that comprises nanoparticles of
silver metal
as well as readily soluble silver salt(s) applied to and disposed on a
substrate. As used
herein, "applied to" and "disposed on" refer to the placement of the silver
onto a substrate
so that the silver and/or silver salt is on a substrate surface and, in the
case of absorbent
materials, may also be distributed within the interior of a substrate (e.g.,
throughout the
absorbent structure between the outermost surfaces).
In embodiments wherein the finished article is to be used as a wound dressing,
an
antimicrobially effective amount of silver is available for delivery from the
article to the
wound bed, or the like. The article typically maintains efficacious levels of
silver release
(e.g., greater than 0.01 mg/g dressing in 100 g water in 30 minutes). The
color of the
finished article is stable (e.g., to heat and light). In certain embodiments
of the invention,
the article is color stable for more than 4 hours, in some embodiments, for
more than 8
hours, and, in some embodiments, longer than 24 hours following exposure of
the article
to visible or UV light. The light stability of the articles of the invention
can be prolonged
by packaging the article in light-proof packaging or storing the article in a
light-free
environment until the article is to be used.
The concentration of silver (in certain embodiments as silver salt, and in
certain
embodiments as a silver salt plus silver metal) on the dried substrate is
preferably less than
about 40,000 milligrams (mg) Ag per kilogram (kg) substrate, and in some
embodiments
less than about 20,000 mg Ag/kg substrate. In still other embodiments, the
concentration
of silver is less than about 10,000 mg Ag/kg substrate.
In embodiments of the invention in which the silver is present as a silver
salt and
silver metal, of the total amount of silver on the substrate, less than 30% is
typically
present as silver metal.
12
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
In some embodiments, the articles of the invention are medical articles such
as
wound dressings and wound packing materials or other material that is applied
directly to
or contacts a wound. However, the articles of the invention may be used in
other
applications (medical and non-medical applications) where the antimicrobial
properties of
silver are needed or desired. Other potential products include clothing,
bedding, masks,
dust cloths, shoe inserts, diapers, and hospital materials such as blankets,
surgical drapes,
and gowns.
The stability of the articles of the invention may be prolonged and/or
increased
when the relative humidity at room temperature is maintained at 50% or lower;
more
preferably at 30% or lower; and most preferably at 20% or lower. Relative
humidity can
be reduced to 30%, and preferably to 20%, or lower for the article of the
invention by a
number of methods including, for example: 1) placing the article in an
environment that
has a relative humidity of 30% or lower, preferably 20% or lower, and then
packaging the
article in the same environment; 2) drying the liquid coated substrate in an
oven and
immediately packaging the resulting article; and/or 3) adding a desiccant
within the
article's packaging. Environments suitable to maintain a low humidity include
packaging
made of material having a low moisture vapor transmission rate (MVTR) such as
a
Techni-Pouch package (e.g., commercially available from Technipaq, Inc.,
Crystal Lake,
IL) with a PET/Aluminum Foil/LLDPE material construction.
In certain embodiments, the articles of the invention are nonadherent,
although it
will be understood that an adhesive (e.g., a pressure sensitive adhesive) can
be applied to
an article in a known manner. Pressure sensitive adhesive suitable for use in
medical
articles can be used in the articles of the present invention. That is, a
pressure sensitive
adhesive can be applied to a surface of the article of this invention to
facilitate adherence
of the article to the skin. The adhesive may be applied, for example, around
the periphery
of a surface of the article so that the silver-containing surface of the
article is adhesively
held to the skin in contact with a wound, or the like. In this manner, under
the moist
conditions of a wound bed, the article will release silver ions into the wound
to prevent
microbial growth.
In certain embodiments, substrates coated with the silver composition can be
covered on one or both sides by a permeable nonadherent outside layer to
reduce adhesion
13
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
and attachment to the wound. The nonadherent layer can be attached to the
substrate by
coating or laminating, for example. Alternatively, the coated substrate can be
enclosed
within a nonadherent layer, such as a sleeve. The nonadherent layer can be
made from
nonadherent woven or nonwoven fabrics such as nylon or perfluorinated-material
coatings
on cotton gauze. The nonadherent layer prevents attachment of the wound
dressing to the
wound. At the same time, the nonadherent layer does not adversely affect the
sustained
release of silver from the coated substrate.
In another embodiment, the substrate or support substrate can be composed of
nonadherent material. For example, a nonadherent hydrophilic polymer can be
used as the
substrate or support material, or coated on a permeable porous substrate, as
described in
U.S. Pat. Pub. Nos. 2004/0180093, 2005/0123590, and 2005/0124724.
If desired, the coated substrate can be covered with two protective films (for
example, thin polyester films). These films optionally may include a nonstick
treatment
and can function to facilitate extraction from a package and in handling the
article. If
desired, the coated substrate can be cut into individual compresses, of sizes
suitable for the
use, packaged in sealed sachets, and sterilized.
Illustrative Embodiments
1. A method of making an antimicrobial article, comprising:
applying a silver composition to a substrate to provide a liquid coated
substrate, the
silver composition comprising a silver salt other than silver sulfate in a
solvent, the silver
composition comprising a stabilizing agent in an amount less than about 100
ppm;
the substrate comprising material selected from the group consisting of
polyamide,
polyester, polyacetate, polyacrylic, polyolefin, polyurethane,
polyvinylchloride, polyvinyl
alcohol, polycarbonate, polyvinylpyrrolidone, polylactic acid, ethylene-vinyl
acetate,
polystyrene, cellulose acetate, polyacrylate, polyacrylamide,
polyacrylonitrile,
polyvinylidene difluoride, polytetrafluoroethylene, polyoxymethylene,
polyvinyl ether,
styrene-ethylenebutylene-styrene elastomer, styrene-butylene-styrene
elastomer, styrene-
isoprene-styrene elastomer, glass fiber, ceramic and combinations of two or
more of the
foregoing; and
drying the liquid coated substrate to provide a color stable antimicrobial
article
comprising silver salt applied to the substrate.
14
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
2. The method of embodiment 1, wherein the silver salt is selected from the
group
consisting of silver acetate, silver benzoate, silver carbonate, silver
chloride, silver citrate,
silver lactate, silver nitrate, silver nitrite, silver chlorite, silver
fluosilicate, silver
trihydrogen paraperiodate, silver levunilate, silver propionate, silver
tartrate, mild silver
protein, silver protein and combinations of two or more of the foregoing.
3. The method of embodiment 2, wherein the silver salt is silver nitrate.
4. The method of embodiment 2, wherein the silver salt is silver benzoate.
5. The method of embodiment 1, wherein the silver salt is selected from the
group
consisting of silver iodate, silver oxalate, silver phosphate, silver
sulfadiazine, silver
saccharinate, silver anthranilate, silver hyponitrite, silver myristate,
silver palmitate, silver
stearate and combinations of two or more of the foregoing.
6. The method of any one of embodiments 1 through 5, wherein the substrate
comprises polyolefin selected from the group consisting of polypropylene,
polyethylene,
ethylene propylene copolymers, ethylene butylene copolymers, and combinations
of two
or more of the foregoing.
7. The method of any one of embodiments 1 through 5, wherein the substrate
comprises polyamide.
8. The method of any one of embodiments 1 through 5, wherein the substrate
comprises cellulose acetate.
9. The method of any one of embodiments 1 through 8, wherein the substrate
comprises material selected from the group consisting of knits, wovens,
nonwovens,
extruded porous sheets, and perforated sheets.
10. The method of any one of embodiments 1 through 9, wherein the silver
composition comprises a stabilizing agent in an amount less than 50 ppm based
on the
total weight of the silver salt composition.
11. The method of embodiment 10, wherein the silver composition comprises no
stabilizing agent.
12. The method of any one of embodiments 1 through 11, wherein drying the
liquid
coated substrate is accomplished at room temperature.
13. The method of any one of embodiments 1 through 11, wherein drying the
liquid
coated substrate is accomplished a temperature less than about 100 C.
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
14. The method of any one of embodiments 1 through 13 wherein the color stable
antimicrobial article comprises silver salt applied to the substrate with a
concentration of
silver on the substrate being less than about 40,000 mg Ag/kg substrate.
15. The method of embodiment 14 wherein the color stable antimicrobial article
comprises silver salt applied to the substrate with a concentration of silver
on the substrate
being less than about 20,000 mg Ag/kg substrate.
16. The method of embodiment 15 wherein the color stable antimicrobial article
comprises silver salt applied to the substrate with a concentration of silver
on the substrate
being less than about 10,000 mg Ag/kg substrate.
17. An article, comprising:
a silver salt other than silver sulfate, the silver salt applied to a
substrate; and
the substrate comprising material selected from the group consisting of
polyamide,
polyester, polyacetate, polyacrylic, polyolefin, polyurethane,
polyvinylchloride, polyvinyl
alcohol, polycarbonate, polyvinylpyrrolidone, polylactic acid, ethylene-vinyl
acetate,
polystyrene, cellulose acetate, polyacrylate, polyacrylamide,
polyacrylonitrile,
polyvinylidene difluoride, polytetrafluoroethylene, polyoxymethylene,
polyvinyl ether,
styrene-ethylenebutylene-styrene elastomer, styrene-butylene-styrene
elastomer, styrene-
isoprene-styrene elastomer, glass fiber, ceramic and combinations of two or
more of the
foregoing; and
wherein the article is antimicrobial and color stable.
18. The article of embodiment 17 wherein the silver salt is selected from the
group
consisting of silver acetate, silver benzoate, silver carbonate, silver
chloride, silver citrate,
silver iodate, silver lactate, silver nitrate, silver nitrite, silver oxalate,
silver phosphate,
silver sulfadiazine, silver saccharinate, silver anthranilate, silver
chlorite, silver
fluosilicate, silver trihydrogen paraperiodate, silver hyponitrite, silver
levunilate, silver
myristate, silver palmitate, silver propionate, silver stearate, silver
tartrate, mild silver
protein, silver protein and combinations of two or more of the foregoing.
19. The article of embodiment 18, wherein the silver salt is selected from the
group
consisting of silver acetate, silver benzoate, silver carbonate, silver
chloride, silver citrate,
silver lactate, silver nitrate, silver nitrite, silver chlorite, silver
fluosilicate, silver
trihydrogen paraperiodate, silver levunilate, silver propionate, silver
tartrate, mild silver
protein, silver protein and combinations of two or more of the foregoing.
16
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
20. The article of embodiment 19, wherein the silver salt is silver nitrate.
21. The article of embodiment 19, wherein the silver salt is silver benzoate.
22. The article of embodiment 18, wherein the silver salt is selected from the
group
consisting of silver iodate, silver oxalate, silver phosphate, silver
sulfadiazine, silver
saccharinate, silver anthranilate, silver hyponitrite, silver myristate,
silver palmitate, silver
stearate and combinations of two or more of the foregoing.
23. The article of any one of embodiments 17 through 22, wherein the substrate
comprises polyamide.
24. The article of any one of embodiments 17 through 22, wherein the substrate
comprises cellulose acetate.
25. The article of any one of embodiments 17 through 24, wherein the
concentration of
silver on the substrate is less than about 40,000 mg Ag/kg substrate.
26. The article of embodiment 25, wherein the concentration of silver on the
substrate
is less than about 20,000 mg Ag/kg substrate.
27. The article of embodiment 26, wherein the concentration of silver on the
substrate
is less than about 10,000 mg Ag/kg substrate.
28. The article of any one of embodiments 17 through 27, wherein the
concentration of
a stabilizing agent is less than about 1000 ppm based on the total weight of
the article.
29. The article of embodiment 28, wherein the concentration of a stabilizing
agent is
less than about 500 ppm based on the total weight of the article.
30. The article of embodiment 29, wherein the concentration of a stabilizing
agent is
less than about 100 ppm, based on the total weight of the article.
31. A method of making an antimicrobial article, comprising:
applying a silver composition to a substrate to provide a liquid coated
substrate, the
silver composition comprising a silver salt selected from the group consisting
of silver
acetate, silver benzoate, silver carbonate, silver chloride, silver citrate,
silver iodate, silver
lactate, silver nitrate, silver nitrite, silver oxalate, silver phosphate,
silver sulfadiazine,
silver saccharinate, silver anthranilate, silver chlorite, silver
fluosilicate, silver trihydrogen
paraperiodate, silver hyponitrite, silver levunilate, silver myristate, silver
palmitate, silver
propionate, silver stearate, silver tartrate, mild silver protein, silver
protein and
combinations of two or more of the foregoing; and
17
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
heating the liquid coated substrate at a temperature sufficient to form silver
metal
from silver salt to provide a color stable antimicrobial article comprising
silver metal
nanoparticles and silver salt.
32. The method of embodiment 31, wherein the silver salt is selected from the
group
consisting of silver acetate, silver benzoate, silver carbonate, silver
chloride, silver citrate,
silver lactate, silver nitrate, silver nitrite, silver chlorite, silver
fluosilicate, silver
trihydrogen paraperiodate, silver levunilate, silver propionate, silver
tartrate, mild silver
protein, silver protein and combinations of two or more of the foregoing.
33. The method of embodiment 32, wherein the silver salt is silver nitrate.
34. The method of embodiment 32, wherein the silver salt is silver benzoate.
35. The method of embodiment 31, wherein the silver salt is selected from the
group
consisting of silver iodate, silver oxalate, silver phosphate, silver
sulfadiazine, silver
saccharinate, silver anthranilate, silver hyponitrite, silver myristate,
silver palmitate, silver
stearate and combinations of two or more of the foregoing.
36. The method of any one of embodiments 31 through 35, wherein the substrate
comprises a material selected from the group consisting of cellulosic
material, nylon,
polyamides, polyacetates, collagen, gelatin, polyacrylamide, natural rubber,
alginates, and
combinations of two or more of the foregoing.
37. The method of embodiment 36, wherein the substrate also comprises material
selected from the group consisting of polyesters, polyacrylics, polyolefins,
polyurethanes,
vinyls including polyvinylchloride, polystyrenes, fiberglass, ceramic fibers,
polyacrylate,
polyacrylonitrile, polyvinylidene difluoride, polytetrafluoroethylene,
polyoxymethylene,
polyvinyl alcohol, polylactic acid, polyvinyl ether, polyvinylpyrrolidone,
polycarbonate,
styrene-ethylenebutylene-styrene elastomer, styrene-butylene-styrene
elastomer, styrene-
isoprene-styrene elastomer and combinations of two or more of the foregoing.
38. The method of embodiment 36 or 37, wherein the substrate comprises
cellulosic
material.
39. The method of embodiment 38, wherein the cellulosic material is absorbent
carboxymethylated material selected from the group consisting of
carboxymethylated
cotton, carboxymethylated cellulose, carboxymethylated solvent-spun cellulose
fibers,
and carboxymethylated rayon and combinations of two or more of the foregoing.
18
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
40. The method of embodiment 38, wherein the cellulosic material is selected
from the
group consisting of cotton, rayon, hemp, jute, bamboo fibers, cellulose
acetate,
carboxymethylated solvent-spun cellulose fibers and combinations of two or
more of the
foregoing.
41. The method of any one of embodiments 31 through 40, wherein the substrate
comprises material selected from the group consisting of knits, wovens,
nonwovens,
extruded porous sheets, and perforated sheets.
42. The method of any one of embodiments 31 through 41, wherein heating the
liquid
coated substrate is accomplished at a temperature within the range from about
95 C to
about 225 C.
43. The method of embodiment 42, wherein heating the liquid coated substrate
is
accomplished at a temperature within the range from about 100 C to about 200
C.
44. The method of embodiment 43, wherein heating the liquid coated substrate
is
accomplished at a temperature within the range from about 110 C to about 180
C.
45. The method of embodiment 44, wherein heating the liquid coated substrate
is
accomplished at a temperature within the range from about 130 C to about 175
C.
46. The method of any one of embodiments 31 through 45, wherein the silver
salt
solution comprises a stabilizing agent in an amount less than 100 ppm based on
the total
weight of the silver composition.
47. The method of embodiment 46, wherein the silver salt solution comprises no
stabilizing agent.
48. The method of any one of embodiments 31 through 47, wherein the
antimicrobial
article is color stable having a non-white color.
49. A method of making an antimicrobial article, comprising:
applying a silver composition to a substrate to provide a liquid coated
substrate, the
silver composition comprising a silver salt other than silver sulfate; and
heating the liquid coated substrate at a temperature sufficient to form silver
metal
from silver salt to provide a color stable antimicrobial article comprising
silver metal
nanoparticles and silver salt.
50. The method of embodiment 49, wherein the silver salt is selected from the
group
consisting of silver acetate, silver benzoate, silver carbonate, silver
chloride, silver citrate,
silver lactate, silver nitrate, silver nitrite, silver chlorite, silver
fluosilicate, silver
19
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
trihydrogen paraperiodate, silver levunilate, silver propionate, silver
tartrate, mild silver
protein, silver protein and combinations of two or more of the foregoing.
51. The method of embodiment 50, wherein the silver salt is silver nitrate.
52. The method of embodiment 50, wherein the silver salt is silver benzoate.
53. The method of embodiment 49, wherein the silver salt is selected from the
group
consisting of silver iodate, silver oxalate, silver phosphate, silver
sulfadiazine, silver
saccharinate, silver anthranilate, silver hyponitrite, silver myristate,
silver palmitate, silver
stearate and combinations of two or more of the foregoing.
54. The method of any one of embodiments 49 through 53, wherein the substrate
comprises material selected from the group consisting of cellulosic material,
nylon,
polyamides, polyacetates, collagen, gelatin, polyacrylamide, natural rubber,
alginates and
combinations of two or more of the foregoing.
55. The method of embodiment 54, wherein the substrate also comprises material
selected from the group consisting of polyesters, polyacrylics, polyolefins,
polyurethanes,
polyvinylchloride, polystyrenes, fiberglass, ceramic fibers, polyacrylate,
polyacrylonitrile,
polyvinylidene difluoride, polytetrafluoroethylene, polyoxymethylene,
polyvinyl alcohol,
polylactic acid, polyvinyl ether, polyvinylpyrrolidone, polycarbonate, styrene-
ethylenebutylene-styrene elastomer, styrene-butylene-styrene elastomer,
styrene-isoprene-
styrene elastomer, and combinations of two or more of the foregoing.
56. The method of embodiment 54 or 55, wherein the substrate comprises
cellulosic
material.
57. The method of embodiment 56, wherein the cellulosic material comprises
absorbent carboxymethylated materials selected from the group consisting of
carboxymethylated cotton, carboxymethylated cellulose, carboxymethylated
solvent-spun
cellulose fibers, and carboxymethylated rayon and combinations of two or more
of the
foregoing.
58. The method of embodiment 56, wherein the cellulosic material is selected
from the
group consisting of cotton, rayon, hemp, jute, bamboo fibers, cellulose
acetate,
carboxymethylated solvent-spun cellulose fibers and combinations of two or
more of the
foregoing.
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
59. The method of any one of embodiments 49 through 58, wherein the substrate
comprises material selected from the group consisting of knits, wovens,
nonwovens,
extruded porous sheets, and perforated sheets.
60. The method of any one of embodiments 49 through 59, wherein heating the
liquid
coated substrate is accomplished at a temperature within the range from about
95 C to
about 225 C.
61. The method of embodiment 60, wherein heating the liquid coated substrate
is
accomplished at a temperature within the range from about 100 C to about 200
C.
62. The method of embodiment 61, wherein heating the liquid coated substrate
is
accomplished at a temperature within the range from about 110 C to about 180
C.
63. The method of embodiment 62, wherein heating the liquid coated substrate
is
accomplished at a temperature within the range from about 130 C to about 175
C.
64. The method of any one of embodiments 49 through 63, wherein the silver
salt
solution comprises a stabilizing agent in an amount less than 100 ppm based on
the total
weight of the silver composition.
65. The method of embodiment 64, wherein the silver salt solution comprises no
stabilizing agent.
66. The method of any one of embodiments 49 through 65, wherein the
antimicrobial
article is color stable having a non-white color.
67. An article, comprising:
silver metal and silver salt disposed on a substrate, the silver salt selected
from the
group consisting of silver acetate, silver benzoate, silver carbonate, silver
chloride, silver
citrate, silver iodate, silver lactate, silver nitrate, silver nitrite, silver
oxalate, silver
phosphate, silver sulfadiazine, silver saccharinate, silver anthranilate,
silver chlorite, silver
fluosilicate, silver trihydrogen paraperiodate, silver hyponitrite, silver
levunilate, silver
myristate, silver palmitate, silver propionate, silver stearate, silver
tartrate, mild silver
protein, silver protein and combinations of two or more of the foregoing.
68. The article of embodiment 67, wherein the silver salt is selected from the
group
consisting of silver acetate, silver benzoate, silver carbonate, silver
chloride, silver citrate,
silver lactate, silver nitrate, silver nitrite, silver chlorite, silver
fluosilicate, silver
trihydrogen paraperiodate, silver levunilate, silver propionate, silver
tartrate, mild silver
protein, silver protein and combinations of two or more of the foregoing.
21
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
69. The article of embodiment 68, wherein the silver salt is silver nitrate.
70. The article of embodiment 68, wherein the silver salt is silver benzoate.
71. The article of embodiment 67, wherein the silver salt is selected from the
group
consisting of silver iodate, silver oxalate, silver phosphate, silver
sulfadiazine, silver
saccharinate, silver anthranilate, silver hyponitrite, silver myristate,
silver palmitate, silver
stearate and combinations of two or more of the foregoing.
72. The article of any one of embodiments 67 through 71, wherein the substrate
comprises a material selected from the group consisting of cellulosic
material, nylon,
polyamides, polyacetates, collagen, gelatin, polyacrylamide, natural rubber,
alginates and
combinations of two or more of the foregoing.
73. The article of embodiment 72, wherein the substrate also comprises
material
selected from the group consisting of polyesters, polyacrylics, polyolefins,
polyurethanes,
polyvinylchloride, polystyrenes, fiberglass, ceramic fibers, polyacrylate,
polyacrylonitrile,
polyvinylidene difluoride, polytetrafluoroethylene, polyoxymethylene,
polyvinyl alcohol,
polylactic acid, polyvinyl ether, polyvinylpyrrolidone, polycarbonate, styrene-
ethylenebutylene-styrene elastomer, styrene-butylene-styrene elastomer,
styrene-isoprene-
styrene elastomer and combinations of two or more of the foregoing.
74. The article of embodiment 72 or embodiment 73, wherein the substrate
comprises
cellulosic material.
75. The article of embodiment 74, wherein the cellulosic material comprise
absorbent
carboxymethylated materials selected from the group consisting of
carboxymethylated
cotton, carboxymethylated cellulose, carboxymethylated solvent-spun cellulose
fibers, and
carboxymethylated rayon and combinations of two or more of the foregoing.
76. The article of embodiment 74, wherein the cellulosic material is selected
from the
group consisting of cotton, rayon, hemp, jute, bamboo fibers, cellulose
acetate,
carboxymethylated solvent-spun cellulose fibers and combinations of two or
more of the
foregoing.
77. The article of any one of embodiments 67 through 76, wherein the substrate
is a
material selected from the group consisting of knits, wovens, nonwovens,
extruded porous
sheets, and perforated sheets.
78. The article of any one of embodiments 67 through 77 wherein the
antimicrobial
article is color stable having a non-white color.
22
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
79. The article of any one of embodiments 67 through 78, wherein the
concentration of
silver on the substrate is less than about 40,000 mg Ag/kg substrate.
80. The article of embodiment 79, wherein the concentration of silver on the
substrate
is less than about 20,000 mg Ag/kg substrate.
81. The article of embodiment 80, wherein the concentration of silver on the
substrate
is less than about 10,000 mg Ag/kg substrate.
82. An article, comprising:
a silver metal and silver salt applied to a substrate, the silver salt
comprising a
silver salt other than silver sulfate.
83. The article of embodiment 82, wherein the silver salt is selected from the
group
consisting of silver acetate, silver benzoate, silver carbonate, silver
chloride, silver citrate,
silver lactate, silver nitrate, silver nitrite, silver chlorite, silver
fluosilicate, silver
trihydrogen paraperiodate, silver levunilate, silver propionate, silver
tartrate, mild silver
protein, silver protein and combinations of two or more of the foregoing.
84. The article of embodiment 83, wherein the silver salt is silver nitrate.
85. The article of embodiment 83, wherein the silver salt is silver benzoate.
86. The article of embodiment 82, wherein the silver salt is selected from the
group
consisting of silver iodate, silver oxalate, silver phosphate, silver
sulfadiazine, silver
saccharinate, silver anthranilate, silver hyponitrite, silver myristate,
silver palmitate, silver
stearate and combinations of two or more of the foregoing.
87. The article of any one of embodiments 82 through 86, wherein the substrate
comprises a material selected from the group consisting of cellulosic
material, nylon,
polyamides, polyacetates, collagen, gelatin, polyacrylamide, natural rubber,
alginates and
combinations of two or more of the foregoing.
88. The article of embodiment 87, wherein the substrate also comprises
material
selected from the group consisting of polyesters, polyacrylics, polyolefins,
polyurethanes,
polyvinylchloride, polystyrenes, fiberglass, ceramic fibers, polyacrylate,
polyacrylonitrile,
polyvinylidene difluoride, polytetrafluoroethylene, polyoxymethylene,
polyvinyl alcohol,
polylactic acid, polyvinyl ether, polyvinylpyrrolidone, polycarbonate, styrene-
ethylenebutylene-styrene elastomer, styrene-butylene-styrene elastomer,
styrene-isoprene-
styrene elastomer and combinations of two or more of the foregoing.
89. The article of embodiment 87 or embodiment 88, wherein the substrate
comprises
23
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
cellulosic material.
90. The article of embodiment 89, wherein the cellulosic material comprise
absorbent
carboxymethylated materials selected from the group consisting of
carboxymethylated
cotton, carboxymethylated cellulose, carboxymethylated solvent-spun cellulose
fibers, and
carboxymethylated rayon and combinations of two or more of the foregoing.
91. The article of embodiment 89, wherein the cellulosic material is selected
from the
group consisting of cotton, rayon, hemp, jute, bamboo fibers, cellulose
acetate,
carboxymethylated solvent-spun cellulose fibers and combinations of two or
more of the
foregoing.
92. The article of any one of embodiments 82 through 91, wherein the substrate
is a
material selected from the group consisting of knits, wovens, extruded porous
sheets, and
perforated sheets.
93. The article of any one of embodiments 82 through 92, wherein the
antimicrobial
article is color stable having a non-white color.
94. The article of any one of embodiments 82 through 93, wherein the
concentration of
silver on the substrate is less than about 40,000 mg Ag/kg substrate.
95. The article of embodiment 94, wherein the concentration of silver on the
substrate
is less than about 20,000 mg Ag/kg substrate.
96. The article of embodiment 95, wherein the concentration of silver on the
substrate
is less than about 10,000 mg Ag/kg substrate.
EXAMPLES
Objects and advantages of this invention are further illustrated by the
following
examples, but the particular materials and amounts thereof recited in these
examples, as
well as other conditions and details, should not be construed to unduly limit
this invention.
Unless otherwise indicated, all parts and percentages are on a weight basis,
all water is
distilled water, and all molecular weights are weight average molecular
weight.
1.
Example I-1
A silver nitrate coating solution was prepared by placing 0.316 grams (g)
silver
nitrate (Aldrich Chemical Co., Milwaukee, WI) and 200 g distilled water in a
glass bottle
24
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
and capping the bottle and mixing at room temperature in a shaker overnight.
Approximately 6 grams of this silver nitrate solution (approximately 1000
micrograms
( g) Ag per gram (g)) solution was coated on an approximately 4-inch x 4-inch
piece of
100% nylon woven from American Fiber and Finishing in Albemarle, NC (SR-823-
32x28,
60 gsm) by transferring the solution by pipette to saturate the mesh that was
contained in a
polystyrene dish. Approximately one gram of coating solution dripped off of
the mesh
before the mesh was suspended in the oven for drying. Some additional solution
dripped
off the mesh in the oven (estimated at 1 g). The coated mesh was dried in a
forced air oven
(Memmert Universal Oven, available from Wisconsin Oven Company, East Troy
Wisconsin) by heating at 80 C for 12 minutes. The resulting material after
drying was
white in appearance. These coated samples were either wrapped in aluminum foil
(protected from light), exposed to fluorescent light (Philips, F32T8/TL735,
Universal/Hi-
Vision, E4) in an environment of approximately 20-30% relative humidity
environment, or
exposed to fluorescent light (Philips, F32T8/TL735, Universal/Hi-Vision, K4)
in an
environment of 45-50% relative humidity. Color ratings of these samples were
measured
over time using a Minolta Chroma Meter (CR-300, manufactured by Konica Minolta
Photo Imaging U.S.A., Inc., Mahwah, NJ). The results are shown in Table I-1.
TABLE I-1. Example I-1 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 28% In foil 90.46 92.38 104.24
2 28% In foil 90.35 92.27 103.81
4 28% In foil 90.25 92.18 104.13
8 28% In foil 90.74 92.66 104.54
24 28% In foil 89.14 91.07 102.49
0 28% exposed 89.86 91.83 102.38
2 28% exposed 87.31 89.10 99.42
4 28% exposed 87.33 89.04 98.99
8 28% exposed 85.79 87.36 95.76
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
24 28% exposed 80.39 81.67 87.63
0 50% exposed 89.75 91.67 102.80
2 50% exposed 85.72 87.38 97.79
4 50% exposed 84.75 86.29 96.40
8 50% exposed 82.21 83.64 92.39
24 50% exposed 74.65 75.76 79.76
Example 1-2
Samples were prepared in same way as Example I-1, except the silver solution
was
silver benzoate (Alfa Aesar; Ward Hill, MA) and this solution was prepared by
placing
0.459 g silver benzoate and 200 g distilled water in a glass bottle. This
resulting silver
benzoate solution was approximately 1000 g Ag/g. The color of the samples was
white.
The results from color monitoring experiments are shown in Table 1-2.
TABLE 1-2. Example 1-2 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 28% In foil 90.39 92.35 103.28
2 28% In foil 89.81 91.79 102.56
4 28% In foil 89.51 91.40 103.01
8 28% In foil 90.78 92.73 102.80
24 28% In foil 87.44 89.39 98.96
0 28% exposed 89.71 91.72 101.82
2 28% exposed 86.34 88.18 97.11
4 28% exposed 82.12 83.79 91.43
8 28% exposed 82.40 83.91 88.86
24 28% exposed 75.94 77.12 78.34
0 50% exposed 89.27 91.23 100.30
2 50% exposed 83.27 84.98 92.34
4 50% exposed 81.03 82.47 87.90
26
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
8 50% exposed 79.02 80.33 82.68
24 50% exposed 67.65 68.40 65.26
Example 1-3 (Comparative)
The color ratings over time at of a commercially available wound dressing were
also measured during exposure to light. This commercially available wound
dressing of
the tradename AQUALCEL Ag, Lot 5F05519 from ConvaTec, contains silver
chloride/silver alginate with high levels of chloride which acts as a
stabilizer and has an
initial off-white color. During exposure to light, the color of the sample
became
noticeably gray. The results from these experiments are shown in Table 1-3.
TABLE 1-3. Example 1-3 (Comparative) Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% In foil 53.51 53.75 64.21
2 12% In foil 53.03 53.30 63.85
4 11% In foil 52.90 53.22 63.91
8 12% In foil 53.40 53.73 64.41
24 11% In foil 53.53 53.66 64.44
48 10% exposed 53.41 53.74 64.57
120 16% exposed 52.31 52.61 63.28
168 18% exposed 52.67 53.01 63.60
0 12% exposed 51.75 52.09 62.71
2 12% exposed 47.28 47.81 57.76
4 11% exposed 46.20 46.58 55.52
8 12% exposed 44.79 45.29 53.37
24 11% exposed 43.30 43.60 50.25
48 10% exposed 41.44 41.67 47.11
120 16% exposed 39.12 39.41 44.70
168 18% exposed 38.12 38.46 43.78
27
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
0 49% exposed 53.06 53.37 63.67
2 49% exposed 47.16 47.76 58.26
4 49% exposed 45.63 46.09 55.69
8 49% exposed 44.07 44.48 53.31
24 49% exposed 40.91 41.25 48.51
48 49% exposed 38.62 38.85 44.85
120 49% exposed 36.54 36.49 41.75
168 49% exposed 34.53 34.42 39.59
Example 1-4
Samples were prepared in same way as Example I-1, except the substrate was a
membrane filter comprised of cellulose nitrate and cellulose acetate (0.22 M
filters,
GSWP 047 00) from Millipore in Billerica, MA. The initial color of the samples
was
white. The results from color monitoring experiments are shown in Table 1-4.
TABLE 1-4. Example 1-4 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 28% In foil 95.85 97.63 113.02
2 28% In foil 95.87 97.65 113.33
4 28% In foil 95.72 97.49 112.31
8 28% In foil 96.16 97.92 113.55
24 28% In foil 95.41 97.16 112.52
0 28% exposed 95.39 97.16 110.68
2 28% exposed 93.85 95.30 108.41
4 28% exposed 93.08 94.36 107.35
8 28% exposed 90.68 91.51 102.44
24 28% exposed 82.39 82.56 88.25
0 50% exposed 96.78 98.66 114.99
28
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
2 50% exposed 95.51 97.18 113.02
4 50% exposed 93.73 95.04 109.09
8 50% exposed 88.85 89.71 97.77
24 50% exposed 75.61 76.06 73.34
Example 1-5
Samples were prepared in same way as Example 1-2, except the substrate was a
membrane filter comprised of cellulose nitrate and cellulose acetate (0.22 M
filters,
GSWP 047 00) from Millipore in Billerica, MA. The initial color of the samples
was
white. The results from color monitoring experiments are shown in Table I-5.
TABLE I-5. Example I-5 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 28% In foil 93.47 95.19 106.56
2 28% In foil 93.23 94.91 106.02
4 28% In foil 93.33 95.04 106.05
8 28% In foil 93.59 95.31 106.54
24 28% In foil 93.98 95.83 108.01
0 28% exposed 94.54 96.26 109.36
2 28% exposed 94.84 96.63 109.90
4 28% exposed 94.71 96.41 109.77
8 28% exposed 94.25 96.01 108.22
24 28% exposed 92.18 94.04 104.00
0 50% exposed 95.32 97.09 111.53
2 50% exposed 94.48 96.22 109.14
4 50% exposed 94.41 96.08 108.78
8 50% exposed 92.65 94.40 103.59
24 50% exposed 89.57 91.64 96.76
29
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
Example 1-6
Samples were prepared in same way as Example I-1, except the substrate was a
100% polyester spunlaced non-woven (SONTARA 8010, 45 gsm) from E. I. du Pont
de
Nemours and Company in Wilmington, DE. This polyester non-woven was wetted by
mechanically inducing the silver nitrate solution into the pores of the
polyester substrate
by fingertips of glove covered hands. (Gloves were SAFESKIN powder free purple
nitrile
exam gloves (Ref 55083 Large) by Kimberly Clark, Roswell, GA). The initial
color of
the samples was white. The results from color monitoring experiments are shown
in Table
1-6.
TABLE 1-6. Example 1-6 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 28% exposed 90.47 92.32 104.25
2 28% exposed 89.24 90.87 102.19
4 28% exposed 88.14 89.48 99.82
6 28% exposed 86.47 87.58 96.84
7.5 28% exposed 84.43 85.31 93.62
11.25 28% exposed 83.32 83.98 90.67
29 28% exposed 76.87 77.16 80.76
0 50% exposed 88.14 89.48 99.82
2 50% exposed 85.21 86.09 94.70
3.5 50% exposed 84.14 84.87 92.88
6 50% exposed 80.86 81.25 87.39
23 50% exposed 75.47 75.78 79.89
Example 1-7
Samples were prepared in same way as Example 1-6, except the silver nitrate
solution was prepared by placing 1.261 g silver nitrate and 200 g distilled
water in a glass
bottle. This resulting silver nitrate solution was approximately 4000 g Ag/g.
The initial
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
color of the samples was white. The results from color monitoring experiments
are shown
in Table 1-7.
TABLE 1-7. Example 1-7 Color with Time
Exposure Relative Exposure CIE Tristimulus Values 5
Time Humidity conditions
x y z
(hr) (%RH)
0 28% exposed 91.49 93.40 106.76
2 28% exposed 90.99 92.76 106.14
4 28% exposed 90.10 91.76 104.65
6 28% exposed 88.57 90.09 100.83
7.5 28% exposed 88.55 90.04 101.03
11.25 28% exposed 88.39 89.79 99.84
29 28% exposed 85.29 86.53 95.58
0 50% exposed 90.10 91.76 104.65
2 50% exposed 88.42 89.94 101.41
3.5 50% exposed 87.29 88.72 99.64
6 50% exposed 86.94 88.14 98.10
23 50% exposed 82.71 83.72 91.35
Example 1-8 (Comparative)
Samples were prepared in same way as Example I-1, except the substrate was a
100% cotton non-woven from Suntec Union, Japan (Nissinbo, AN20601050 60 gsm,
containing less than 50 ppm chloride). The initial color of the samples was
off white. The
results from color monitoring experiments are shown in Table 1-8.
TABLE 1-8. Example 1-8 (Comparative) Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 28% in foil 90.11 92.05 103.38
31
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
2 28% in foil 88.36 90.24 100.54
4 28% in foil 89.33 91.28 101.61
8 28% in foil 89.45 91.36 101.37
24 28% in foil 87.69 89.60 98.82
0 28% exposed 89.91 91.83 102.77
2 28% exposed 81.82 82.87 91.87
4 28% exposed 74.05 74.31 81.64
8 28% exposed 64.83 64.22 67.01
24 28% exposed 44.04 43.82 45.43
0 50% exposed 91.11 93.06 105.01
2 50% exposed 84.35 85.39 94.23
4 50% exposed 76.12 76.24 81.43
8 50% exposed 57.88 56.99 57.51
24 50% exposed 36.17 36.59 35.92
Example 1-9 (Comparative)
Samples were prepared in same way as Example 1-2, except the substrate was a
100% cotton non-woven from Suntec Union, Japan (Nissinbo, AN20601050 60 gsm,
containing less than 50 ppm chloride). The initial color of the samples was
off white. The
results from color monitoring experiments are shown in Table 1-9.
TABLE 1-9. Example 1-9 (Comparative) Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 28% in foil 88.51 90.40 98.82
2 28% in foil 87.96 89.84 97.60
4 28% in foil 88.26 90.13 97.57
8 28% in foil 88.29 90.18 97.03
24 28% in foil 86.37 88.27 93.35
0 28% exposed 90.06 91.99 102.55
32
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
2 28% exposed 86.96 88.49 97.45
4 28% exposed 83.47 84.56 92.26
8 28% exposed 75.28 75.27 79.70
24 28% exposed 54.60 54.14 56.55
0 50% exposed 88.58 90.47 99.23
2 50% exposed 82.85 83.98 90.29
4 50% exposed 75.59 75.77 81.13
8 50% exposed 60.09 59.35 62.85
24 50% exposed 34.42 35.74 37.87
Example 1-10 (Comparative)
Samples were prepared in same way as Example I-1, except the substrate was a
non-woven of 70% Viscose/30% PET fibers (507030RPET P1, white, 50 gsm) from
FA-MA JERSEY s.p.a in Italy. The initial color of the samples was off white.
The
results from color monitoring experiments are shown in Table 1-10.
TABLE I-10. Example I-10 (Comparative) Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
X Y Z
(hr) (%RH)
0 28% in foil 81.37 82.74 86.19
2 28% in foil 80.15 81.31 84.22
4 28% in foil 81.30 82.52 86.23
8 28% in foil 80.10 81.18 84.08
24 28% in foil 78.68 79.73 82.21
0 28% exposed 84.09 85.69 90.95
2 28% exposed 40.47 41.03 45.52
4 28% exposed 34.16 34.53 38.44
8 28% exposed 27.04 27.02 29.61
24 28% exposed 22.53 22.32 23.17
0 50% exposed 83.47 84.96 88.89
33
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
2 50% exposed 36.60 36.75 40.03
4 50% exposed 30.65 30.61 33.06
8 50% exposed 24.80 24.51 24.75
24 50% exposed 19.87 19.56 16.79
Example I-11 (Comparative)
Samples were prepared in same way as Example 1-2, except the substrate was a
non-woven of 70% Viscose/30% PET fibers (507030RPET P1, white, 50 gsm) from
FA-MA JERSEY s.p.a in Italy. The initial color of the samples was off white.
The
results from color monitoring experiments are shown in Table I-11.
TABLE I-11. Example I-11 (Comparative) Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
X Y Z
(hr) (%RH)
0 28% in foil 83.81 85.50 89.18
2 28% in foil 83.26 84.89 88.50
4 28% in foil 83.92 85.59 89.66
8 28% in foil 82.67 84.25 87.58
24 28% in foil 81.72 83.42 86.21
0 28% exposed 85.94 87.80 92.68
2 28% exposed 50.71 51.40 58.32
4 28% exposed 42.69 43.07 48.42
8 28% exposed 32.40 31.80 33.98
24 28% exposed 24.65 24.29 24.94
0 50% exposed 84.83 86.65 90.38
2 50% exposed 45.73 46.53 51.53
4 50% exposed 37.08 37.04 39.38
8 50% exposed 28.42 27.50 26.63
24 50% exposed 19.13 17.95 14.25
34
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
Example 1-12 (Comparative)
Samples were prepared in same way as Example I-1, except the substrate was a
non-woven of 70% LYOCELL fibers/30% PET (SX-156, white, 50 gsm, FT-10
apertured)
from Ahlstrom Green Bay, Inc. in Green Bay, WI that contained less than 40 ppm
chloride. The initial color of the samples was off white. The results from
color
monitoring experiments are shown in Table 1-12.
TABLE I-12. Example I-12 (Comparative) Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x Y Z
(hr) (%RH)
0 28% in foil 82.78 83.66 90.59
2 28% in foil 82.40 83.23 90.07
4 28% in foil 82.70 83.49 90.27
8 28% in foil 82.50 83.21 89.90
24 28% in foil 80.46 81.05 87.50
0 28% exposed 84.02 85.04 91.42
2 28% exposed 41.48 41.60 46.75
4 28% exposed 32.67 32.97 38.11
8 28% exposed 28.61 29.01 33.61
24 28% exposed 23.99 24.36 28.34
0 50% exposed 84.96 86.10 93.01
2 50% exposed 40.73 40.84 46.51
4 50% exposed 33.88 34.04 39.12
8 50% exposed 29.17 29.43 33.70
24 50% exposed 25.38 25.52 27.80
II.
Example 11-1
A silver nitrate coating solution was prepared by placing 0.0792 g silver
nitrate
(Aldrich Chemical Co., Milwaukee, WI) and 200 g distilled water in a glass
bottle and
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
capping the bottle and mixing at room temperature in a shaker overnight.
Approximately
6 grams of this silver nitrate solution (approximately 250 g Ag/g) solution
was coated on
a 4-inch x 4-inch piece of 100% cotton non-woven from Suntec Union, Japan
(Nissinbo,
AN20601050 60 gsm, containing less than 50 ppm chloride) by transferring the
solution
by pipette to saturate the mesh that was contained in a polystyrene dish.
Approximately
one gram of coating solution dripped off of the mesh before the mesh was
suspended in
the oven for drying. Some additional solution dripped off the mesh in the oven
(estimated
at 1 g). The coated mesh was dried in a forced air oven (Memmert Universal
Oven,
available from Wisconsin Oven Company, East Troy Wisconsin) by heating at 105
C for
12 minutes. The resulting material after drying was white in appearance. These
coated
samples were either wrapped in aluminum foil (protected from light), exposed
to
fluorescent light (Philips, F32T8/TL735, Universal/Hi-Vision, E4) in an
environment of
approximately 10-20% relative humidity environment, or exposed to fluorescent
light
(Philips, F32T8/TL735, Universal/Hi-Vision, K4) in an environment of 45-50%
relative
humidity. Color ratings of these samples were measured over time using a
Minolta
Chroma Meter (CR-300, manufactured by Konica Minolta Photo Imaging U.S.A.,
Inc.,
Mahwah, NJ). The results are shown in Table II-1.
After the color stability test were completed, samples that were protected in
foil
and samples that were exposed to fluorescent light at 10-20% relative humidity
were
analyzed for silver ion release. Silver release from the aforementioned
samples was
measured in a solution of distilled water and sodium nitrate using a silver
ion selective
electrode (Orion, available VWR International, Batavia, IL). A sample of
0.1341 g that
was exposed to light for 168 hr at approximately 20% relative humidity
released 0.45 mg
silver ion per gram of sample within 30 minutes of placing the sample in 98
grams
distilled water and 2.96 grams of 5M sodium nitrate. By comparison, a 0.1140 g
sample
that was kept in foil during the 168 hours released 1.23 mg of silver ion per
gram of
sample into 98 grams of distilled water and 2.96 grams of sodium nitrate.
Total silver content measurements were also conducted in duplicate on coated
sample that were kept in foil. For silver content, samples were first digested
using nitric
acid and hydrogen peroxide (See EPA Method 6010), and then total silver was
measured
using Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES;
Varian,
Vista-Pro, AX). The average silver content was 1700 mg Ag/kg sample. Silver
metal
36
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
analysis was performed by first extracting a sample overnight with a 2.8%
(w/w)
ammonium carbonate solution at room temperature. The leachate was then
discarded, and
the samples were digested and silver content determined as above. For a sample
that was
kept in the foil, the silver metal content of the sample was 120 mg/kg sample.
TABLE II-1. Example II-1 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 87.06 89.1 94.7
2 12% in foil 87.72 89.78 95.72
4 11% in foil 87.64 89.71 95.25
8 12% in foil 87.48 89.55 95.18
24 11% in foil 87.88 89.96 95.82
48 10% in foil 88.22 90.26 96.36
120 16% in foil 87.86 89.92 95.7
168 18% in foil 87.23 89.32 94.6
0 12% exposed 86.35 88.3 92.01
2 12% exposed 86.04 87.89 92.59
4 11% exposed 85.94 84.68 92.96
8 12% exposed 84.49 86.08 91.04
24 11% exposed 82.21 83.44 88.22
48 10% exposed 77.79 78.39 82.1
120 16% exposed 68.61 69.08 71.7
168 18% exposed 65.85 66.99 68.05
0 49% exposed 86.51 88.49 92.2
2 49% exposed 86.08 87.89 92.25
4 49% exposed 84.66 86.1 90.86
8 48% exposed 78.49 79.18 81.62
24 47% exposed 59.77 60.04 61.67
37
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
48 47% exposed 47.43 48.48 49.18
120 47% exposed 39.56 40.73 36.79
168 47% exposed 36.64 37.83 33.51
Example 11-2 (Control)
The color ratings over time of the uncoated cotton substrate used in Example
II-1
were also measured. These results are included in Table 11-2.
TABLE 11-2. Example 11-2 (Control) - Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 92.55 94.58 107.96
2 12% in foil 92.55 94.53 107.93
4 11% in foil 92.42 94.37 107.9
8 12% in foil 92.57 94.54 108.2
24 11% in foil 92.53 94.54 107.99
48 10% in foil 92.85 94.83 108.54
120 16% in foil 92.9 94.88 108.61
168 18% in foil 92.6 94.65 108.2
Example 11-3 (Comparative)
The color ratings over time of a commercially available wound dressing were
also
measured during exposure to light. This commercially available wound dressing,
available under the tradename AQUACEL Ag, Lot 5F05519, from ConvaTec, contains
silver chloride/silver alginate with high levels of chloride which acts as a
stabilizer and has
an initial off-white color. During exposure to light, the color of the sample
became
noticeably gray. The results from these experiments are shown in Table 11-3.
TABLE 11-3. Example 11-3 (Comparative) Color with Time
Exposure Relative Exposure CIE Tristimulus Values
38
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 53.51 53.75 64.21
2 12% in foil 53.03 53.30 63.85
4 11% in foil 52.90 53.22 63.91
8 12% in foil 53.40 53.73 64.41
24 11% in foil 53.53 53.66 64.44
48 10% in foil 53.41 53.74 64.57
120 16% in foil 52.31 52.61 63.28
168 18% in foil 52.67 53.01 63.60
0 12% exposed 51.75 52.09 62.71
2 12% exposed 47.28 47.81 57.76
4 11% exposed 46.20 46.58 55.52
8 12% exposed 44.79 45.29 53.37
24 11% exposed 43.30 43.60 50.25
48 10% exposed 41.44 41.67 47.11
120 16% exposed 39.12 39.41 44.70
168 18% exposed 38.12 38.46 43.78
0 49% exposed 53.06 53.37 63.67
2 49% exposed 47.16 47.76 58.26
4 49% exposed 45.63 46.09 55.69
8 48% exposed 44.07 44.48 53.31
24 47% exposed 40.91 41.25 48.51
48 47% exposed 38.62 38.85 44.85
120 47% exposed 36.54 36.49 41.75
168 47% exposed 34.53 34.42 39.59
Example 11-4
Samples were prepared in same way as Example II-1, except the silver nitrate
solution was prepared by placing 0.316 g silver nitrate and 200 g distilled
water in a glass
bottle. This resulting silver nitrate solution was approximately 1000 g Ag/g.
The color
39
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
of the samples was off-white. The results from color monitoring experiments
are shown in
Table 11-4.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1320 grams of the sample that was
exposed to
light for 168 hr at approximately 20% relative humidity released 4.46 mg
silver ion per
gram of sample within 30 minutes of placing the sample in 98 grams distilled
water and
2.96 grams of 5M sodium nitrate. By comparison, a 0.1626 g sample that was
kept in foil
during the 168 hours released 5.21 mg of silver ion per gram of sample into 98
grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
6950 mg Ag/kg sample. The silver metal content was 350 mg/kg sample.
TABLE 11-4. Example 11-4 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 80.95 82.71 80.89
2 12% in foil 80.80 82.54 80.47
4 11% in foil 81.81 83.56 81.88
8 12% in foil 81.12 82.82 80.73
24 11% in foil 81.23 82.93 80.77
48 10% in foil 81.15 82.85 80.58
120 16% in foil 81.01 82.7 80.37
168 18% in foil 80.82 82.51 79.83
0 12% exposed 81.13 82.87 82.42
2 12% exposed 81.07 82.79 81.84
4 11% exposed 80.91 82.53 82.16
8 12% exposed 79.77 81.24 80.65
24 11% exposed 77.4 78.46 75.52
48 10% exposed 72.71 73.19 68.73
120 16% exposed 60.66 60.53 53.36
168 18% exposed 51.71 51.63 44.89
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
0 49% exposed 81.53 83.26 81.2
2 49% exposed 79.98 81.49 78.29
4 49% exposed 78.76 80.02 76.25
8 48% exposed 75.06 75.86 71.43
24 47% exposed 59.73 60.29 55.57
48 47% exposed 48.01 48.98 43.13
120 47% exposed 30.68 30.97 20.96
168 47% exposed 27.78 27.99 18.12
Example 11-5
Samples were prepared in same way as Example II-1, except the drying
temperature was 130 C. The color of the samples was cream (light yellow). The
results
from color monitoring experiments are shown in Table II-5.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1341 grams of the sample that was
exposed to
light for 168 hr at approximately 20% relative humidity released 0.49 mg
silver ion per
gram of sample within 30 minutes of placing the sample in 98 grams distilled
water and
2.96 grams of 5M sodium nitrate. By comparison, a 0.1280 g sample that was
kept in foil
during the 168 hours released 1.06 mg of silver ion per gram of sample into 98
grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
2000 mg Ag/kg sample. The silver metal content was 160 mg/kg sample.
TABLE II-5. Example II-5 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 69.49 70.83 48.26
2 12% in foil 70.01 71.37 48.99
4 11% in foil 69.90 71.23 48.73
8 12% in foil 69.32 70.57 47.78
24 11% in foil 69.76 71.02 48.57
41
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
48 10% in foil 69.68 70.92 48.05
120 16% in foil 69.53 70.73 48.18
168 18% in foil 69.56 70.83 48.09
0 12% exposed 69.00 70.17 48.40
2 12% exposed 68.53 69.63 48.37
4 11% exposed 68.82 69.91 48.72
8 12% exposed 67.16 68.08 46.75
24 11% exposed 65.74 66.32 45.88
48 10% exposed 63.61 63.80 44.50
120 16% exposed 55.74 55.41 38.01
168 18% exposed 50.82 50.69 35.80
0 49% exposed 68.68 69.72 50.85
2 49% exposed 66.61 67.34 47.24
4 49% exposed 65.34 65.81 45.74
8 48% exposed 62.47 62.50 44.00
24 47% exposed 51.69 50.97 37.77
48 47% exposed 41.88 42.00 33.19
120 47% exposed 35.46 36.24 28.98
168 47% exposed 31.18 31.89 26.85
Example 11-6
Samples were prepared in same way as Example 11-4, except the drying
temperature was 130 C. The color of the samples was light yellow. The results
from
color monitoring experiments are shown in Table 11-6.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1376 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 4.28 mg silver ion
per gram of
sample within 30 minutes of placing the sample in 98 grams distilled water and
2.96
grams of 5M sodium nitrate. By comparison, a 0.1462 gram sample that was kept
in foil
during the 168 hours released 5.18 mg of silver ion per gram of sample into 98
grams of
42
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
7650 mg Ag/kg sample. The silver metal content was 530 mg/kg sample.
TABLE 11-6. Example 11-6 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 55.09 54.35 32.83
2 12% in foil 54.89 54.13 32.89
4 11% in foil 55.37 54.65 33.23
8 12% in foil 54.72 53.98 32.83
24 11% in foil 55.50 54.77 33.61
48 10% in foil 55.83 55.14 33.67
120 16% in foil 56.72 56.16 34.03
168 18% in foil 55.71 55.05 33.62
0 12% exposed 57.41 57.16 36.86
2 12% exposed 57.39 57.18 37.32
4 11% exposed 58.53 58.32 37.92
8 12% exposed 56.98 56.66 36.61
24 11% exposed 56.42 55.93 35.89
48 10% exposed 54.61 53.86 33.79
120 16% exposed 50.06 48.96 30.27
168 18% exposed 45.73 44.54 27.05
0 49% exposed 55.70 54.92 32.57
2 49% exposed 55.72 54.96 31.58
4 49% exposed 54.78 53.85 30.23
8 48% exposed 53.14 52.06 29.52
24 47% exposed 48.62 47.21 25.68
48 47% exposed 39.26 38.29 21.27
120 47% exposed 26.10 24.96 14.83
168 47% exposed 23.89 22.17 11.66
43
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
Example 11-7
Samples were prepared in same way as Example II-1, except the drying
temperature was 155 C. The color of the samples was yellow. The results from
color
monitoring experiments are shown in Table 11-7.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1426 grams of the sample that was
exposed to
light for 168 hr at approximately 20% relative humidity released 0.31 mg
silver ion per
gram of sample within 30 minutes of placing the sample in 98 grams distilled
water and
2.96 grams of 5M sodium nitrate. By comparison, a 0.1307 g sample that was
kept in foil
during the 168 hours released 0.95 mg of silver ion per gram of sample into 98
grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
1850 mg Ag/kg sample. The silver metal content was 250 mg/kg sample.
TABLE 11-7. Example 11-7 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 57.24 57.13 28.24
2 12% in foil 56.37 56.15 27.74
4 11% in foil 59.84 60.15 30.51
8 12% in foil 59.49 59.72 30.29
24 11% in foil 59.78 60.01 30.63
48 10% in foil 58.90 59.02 29.69
120 16% in foil 59.27 59.34 30.30
168 18% in foil 60.24 60.47 31.04
0 12% exposed 55.48 55.08 28.47
2 12% exposed 55.62 55.20 28.86
4 11% exposed 55.59 55.09 28.40
8 12% exposed 55.11 54.60 28.20
24 11% exposed 53.33 52.59 27.03
48 10% exposed 53.40 52.66 27.73
44
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
120 16% exposed 50.43 49.57 26.12
168 18% exposed 46.73 45.74 23.78
0 49% exposed 59.25 59.66 33.23
2 49% exposed 58.72 58.97 32.67
4 49% exposed 58.63 58.92 32.40
8 48% exposed 57.94 58.22 31.47
24 47% exposed 55.49 55.46 30.25
48 47% exposed 53.18 53.3 28.88
120 47% exposed 45.51 45.67 26.09
168 47% exposed 39.02 39.03 25.11
Example 11-8
Samples were prepared in same way as Example 11-4, except the drying
temperature was 155 C. The color of the samples was yellow. The results from
color
monitoring experiments are shown in Table 11-8.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1366 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 2.49 mg silver ion
per gram of
sample within 30 minutes of placing the sample in 98 grams distilled water and
2.96
grams of 5M sodium nitrate. By comparison, a 0.1351 g sample that was kept in
foil
during the 168 hours released 4.97 mg of silver ion per gram of sample into 98
grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
6900 mg Ag/kg sample. The silver metal content was 900 mg/kg sample.
TABLE 11-8. Example 11-8 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 42.65 41.24 19.00
2 12% in foil 42.95 41.49 18.57
4 11% in foil 43.07 41.59 18.71
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
8 12% in foil 43.22 41.73 19.15
24 11% in foil 43.25 41.76 18.85
48 10% in foil 43.40 41.90 19.05
120 16% in foil 43.98 42.50 19.43
168 18% in foil 43.88 42.40 19.27
0 12% exposed 43.55 45.33 18.81
2 12% exposed 44.10 42.86 19.08
4 11% exposed 43.80 42.56 18.89
8 12% exposed 43.29 41.99 18.44
24 11% exposed 42.88 41.53 18.91
48 10% exposed 42.11 40.70 17.65
120 16% exposed 39.80 38.31 16.75
168 18% exposed 36.54 35.29 16.27
0 49% exposed 42.34 40.96 18.32
2 49% exposed 43.11 41.64 17.39
4 49% exposed 42.19 40.68 17.74
8 48% exposed 41.40 39.90 17.04
24 47% exposed 38.31 36.62 16.24
48 47% exposed 33.94 32.50 13.97
120 47% exposed 26.01 24.71 10.66
168 47% exposed 23.28 21.99 10.32
Example 11-9
Samples were prepared in same way as Example 11-8, except the silver nitrate
solution was prepared by placing 0.632 g silver nitrate and 200 g distilled
water in a glass
bottle. This resulting silver nitrate solution was approximately 2000 g Ag/g.
The color
of the samples was golden yellow. The results from color monitoring
experiments are
shown in Table 11-9.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1308 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 9.2 mg silver ion
per gram of
46
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
sample within 30 minutes of placing the sample in 98 grams distilled water and
2.96
grams of 5M sodium nitrate. By comparison, a 0.1431 g sample that was kept in
foil
during the 168 hours released 10.8 mg of silver ion per gram of sample into 98
grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
16,000 mg Ag/kg sample. The silver metal content was 1400 mg/kg sample.
TABLE 11-9. Example 11-9 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 41.74 40.74 19.36
2 12% in foil 41.63 40.58 19.29
4 11% in foil 41.48 40.54 19.99
8 12% in foil 42.00 40.91 19.51
24 11% in foil 42.41 41.35 19.55
48 10% in foil 42.21 41.18 19.83
120 16% in foil 42.31 41.29 19.98
168 18% in foil 42.98 41.99 20.03
0 12% exposed 40.59 39.38 18.64
2 12% exposed 40.89 39.71 19.49
4 11% exposed 40.95 39.76 20.07
8 12% exposed 40.05 38.84 19.99
24 11% exposed 40.65 39.33 18.52
48 10% exposed 40.20 38.89 18.66
120 16% exposed 38.79 37.25 16.35
168 18% exposed 36.05 34.41 16.96
0 49% exposed 40.24 39.12 19.14
2 49% exposed 40.54 39.19 17.30
4 49% exposed 41.31 40.15 18.37
8 48% exposed 40.61 39.35 17.70
24 47% exposed 38.43 36.78 15.89
47
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
48 47% exposed 34.27 32.43 13.77
120 47% exposed 24.06 21.72 10.56
168 47% exposed 21.06 18.68 9.53
Example 11-10
Samples were prepared in same way as Example 11-8, except the silver solution
was silver benzoate (Alfa Aesar; Ward Hill, MA), which was prepared by placing
0.230 g
silver benzoate and 200 g distilled water in a glass bottle. This resulting
silver benzoate
solution was approximately 500 g Ag/g. The color of the samples was yellow.
The
results from color monitoring experiments are shown in Table 11-10.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1341 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 0.22 mg silver ion
per gram of
sample within 30 minutes of placing the sample in 98 grams distilled water and
2.96
grams of 5M sodium nitrate. By comparison, a 0.1323 g sample that was kept in
foil
during the 168 hours released 0.71 mg of silver ion per gram of sample into 98
grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
3350 mg Ag/kg sample.
TABLE II-10. Example II-10 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 41.83 41.21 18.15
2 12% in foil 42.09 41.5 18.44
4 11% in foil 42.19 41.65 18.64
8 12% in foil 42.27 41.71 18.61
24 11% in foil 42.27 41.72 19.44
48 10% in foil 42.28 41.7 19.06
120 16% in foil 42.57 41.82 18.63
168 18% in foil 42.55 41.84 19.14
48
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
0 12% exposed 42.94 42.37 18.87
2 12% exposed 42.19 41.67 19.99
4 11% exposed 42.07 41.57 19.87
8 12% exposed 42.27 41.81 19.65
24 11% exposed 42.05 41.6 19.25
48 10% exposed 41.78 41.33 19.82
120 16% exposed 42.19 41.68 20.01
168 18% exposed 42.12 41.58 19.92
0 49% exposed 41.04 40.65 19.67
2 49% exposed 41.85 41.34 18.70
4 49% exposed 40.04 39.42 19.00
8 48% exposed 39.79 39.11 18.73
24 47% exposed 39.86 39.11 18.04
48 47% exposed 39.21 38.24 17.61
120 47% exposed 38.06 37.14 17.32
168 47% exposed 36.47 35.68 17.83
Example 11-11
Samples were prepared in same way as Example 11-10, except the silver solution
was silver benzoate and this solution was prepared by placing 0.459 g silver
benzoate and
200 g distilled water in a glass bottle. This resulting silver benzoate
solution was
approximately 1000 g Ag/g. The color of the samples was yellow. The results
from
color monitoring experiments are shown in Table II-11.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1352 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 0.80 mg silver ion
per gram of
sample within 30 minutes of placing the sample in 98 grams distilled water and
2.96
grams of 5M sodium nitrate. By comparison, a 0.1502 g sample that was kept in
foil
during the 168 hours released 1.50 mg of silver ion per gram of sample into 98
grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
6750 mg Ag/kg sample.
49
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
TABLE II-11. Example II-11 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 31.49 30.33 13.40
2 12% in foil 32.21 31.07 13.62
4 11% in foil 32.49 31.36 13.49
8 12% in foil 32.37 31.18 13.72
24 11% in foil 32.32 31.14 13.74
48 10% in foil 32.44 31.21 13.46
120 16% in foil 32.64 31.38 13.61
168 18% in foil 32.36 31.07 13.82
0 12% exposed 32.48 31.33 13.78
2 12% exposed 32.21 31.05 13.34
4 11% exposed 32.01 30.85 13.26
8 12% exposed 32.30 31.19 13.56
24 11% exposed 31.73 30.64 13.32
48 10% exposed 31.63 30.57 13.56
120 16% exposed 31.57 30.43 13.30
168 18% exposed 31.69 30.53 13.37
0 49% exposed 33.00 31.91 13.92
2 49% exposed 32.78 31.55 12.98
4 49% exposed 32.73 31.47 13.07
8 48% exposed 32.31 31.06 13.34
24 47% exposed 32.32 30.94 12.76
48 47% exposed 31.23 29.74 12.45
120 47% exposed 29.81 28.41 11.76
168 47% exposed 28.60 27.49 12.22
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
Example 11-12
Samples were prepared in same way as Example II-11, except the substrate was a
non-woven of 100% TENCEL fibers (SX-152, white, 65 gsm, 24 mesh, from Green
Bay
Nonwovens, Inc. in Green Bay, WI) that contained less than 40 ppm chloride.
The color
of the samples was golden brown. The results from color monitoring experiments
are
shown in Table 11-12.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1662 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 1.61 mg silver ion
per gram of
sample within 30 minutes of placing the sample in 98 grams distilled water and
2.96
grams of 5M sodium nitrate. By comparison, a 0.1524 g sample that was kept in
foil
during the 168 hours released 2.34 mg of silver ion per gram of sample into 98
grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
7650 mg Ag/kg sample.
TABLE II-12. Example II-12 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 22.92 21.10 6.51
2 12% in foil 22.88 21.02 6.43
4 11% in foil 22.58 20.73 6.32
8 12% in foil 22.94 21.09 6.35
24 11% in foil 22.91 21.06 6.30
48 10% in foil 23.00 21.12 6.26
120 16% in foil 22.88 20.96 6.15
168 18% in foil 23.60 21.63 6.52
0 12% exposed 22.97 21.26 6.68
2 12% exposed 23.83 22.10 6.68
4 11% exposed 24.22 22.52 6.88
8 12% exposed 24.08 22.38 6.82
51
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
24 11% exposed 24.40 22.75 6.86
48 10% exposed 24.26 22.61 6.83
120 16% exposed 23.40 21.79 6.88
168 18% exposed 24.39 22.71 6.88
0 49% exposed 23.00 21.19 6.54
2 49% exposed 22.42 20.68 6.19
4 49% exposed 21.15 19.56 6.05
8 48% exposed 20.44 19.02 6.13
24 47% exposed 18.46 17.48 6.03
48 47% exposed 17.00 16.42 6.06
120 47% exposed 15.90 15.79 6.48
168 47% exposed 16.04 16.07 6.91
Example 11-13
Samples were prepared in same way as Example 11-4, except the drying
temperature was 180 C. The color of the samples was golden yellow. The results
from
color monitoring experiments are shown in Table II-13.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1476 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 0.44 mg silver ion
per gram of
sample within 30 minutes of placing the sample in 98 grams distilled water and
2.96
grams of 5M sodium nitrate. By comparison, a 0.1550 g sample that was kept in
foil
during the 168 hours released 0.88 mg of silver ion per gram of sample into 98
grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
6900 mg Ag/kg sample. The silver metal content was 1200 mg/kg sample.
TABLE II-13. Example II-13 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 30.67 29.37 9.41
52
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
2 12% in foil 31.03 29.79 9.95
4 11% in foil 31.08 29.83 9.98
8 12% in foil 31.09 29.90 9.90
24 11% in foil 31.17 29.92 9.95
48 10% in foil 31.10 29.81 9.88
120 16% in foil 31.19 29.81 9.98
168 18% in foil 31.24 29.85 10.07
0 12% exposed 30.09 28.75 10.25
2 12% exposed 30.34 28.93 9.95
4 11% exposed 30.02 28.60 10.13
8 12% exposed 29.49 28.15 10.48
24 11% exposed 29.50 28.11 10.35
48 10% exposed 29.38 28.02 10.58
120 16% exposed 29.12 27.95 10.81
168 18% exposed 27.98 26.98 10.64
0 49% exposed 33.28 32.32 11.46
2 49% exposed 34.46 33.41 11.48
4 49% exposed 34.49 33.44 11.48
8 48% exposed 33.89 32.85 11.26
24 47% exposed 33.50 32.57 11.44
48 47% exposed 32.46 31.58 11.08
120 47% exposed 30.71 30.02 10.93
168 47% exposed 30.15 29.55 10.82
Example 11-14
Samples were prepared in same way as Example 11-10, except the silver solution
was comprised of 0. 127 g of silver carbonate (Alfa Aesar, Ward Hill, MA),
0.48 g of
ammonium carbonate (Mallinckroft Baker, Inc.; Phillipsburg, NJ), and 100 g
distilled
water. The color of the coated cotton samples was golden yellow. The results
from color
monitoring experiments are shown in Table II-14.
53
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1386 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 0.44 mg silver ion
per gram of
sample within 30 minutes of placing the sample in 98 grams distilled water and
2.96
grams of 5M sodium nitrate. By comparison, a 0.1498 g sample that was kept in
foil
during the 168 hours released 0.48 mg of silver ion per gram of sample into 98
grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
8150 mg Ag/kg sample.
TABLE II-14. Example II-14 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 34.39 32.41 12.16
2 12% in foil 34.87 33.16 12.96
4 11% in foil 34.95 33.32 13.79
8 12% in foil 35.40 33.71 13.74
24 11% in foil 34.94 33.01 12.97
48 10% in foil 34.48 32.62 13.61
120 16% in foil 34.28 32.23 13.50
168 18% in foil 34.30 31.99 12.57
0 12% exposed 31.50 29.39 10.26
2 12% exposed 30.83 28.74 10.04
4 11% exposed 32.22 30.21 10.55
8 12% exposed 31.59 29.50 10.23
24 11% exposed 31.64 29.44 10.42
48 10% exposed 32.02 29.80 10.32
120 16% exposed 31.69 29.43 10.21
168 18% exposed 31.98 29.75 10.22
0 49% exposed 30.65 28.7 10.66
2 49% exposed 30.23 28.08 9.90
54
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
4 49% exposed 30.60 28.47 10.17
8 48% exposed 30.41 28.29 10.15
24 47% exposed 30.65 28.61 10.64
48 47% exposed 30.88 28.85 10.31
120 47% exposed 30.69 28.68 10.35
168 47% exposed 30.80 28.86 10.35
Example 11-15
Samples were prepared in same way as Example 11-10, except the silver solution
was silver acetate and this solution was prepared by placing 0.309 g silver
acetate
(Matheson, Coleman, and Bell; Norwood, OH) and 200 g distilled water in a
glass bottle,
and the drying temperature was 170 C. This resulting silver acetate solution
was
approximately 1000 g Ag/g. The color of the samples was yellow. The results
from
color monitoring experiments are shown in Table II-15.
Silver ion release measurements were conducted as described in Example II-1.
An
amount of 0.1525 g of the sample that was exposed to light for at least 14
days at
approximately 20% relative humidity released 0.71 mg silver ion per gram of
sample
within 30 minutes of placing the sample in 98 grams distilled water and 2.96
grams of 5M
sodium nitrate. By comparison, a 0.1528 g sample that was kept foil for during
the
experiment released 0.69 mg of silver ion per gram of sample into 98 grams of
distilled
water and 2.96 grams of sodium nitrate.
TABLE II-15. Example II-15 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
1 20% in foil 34.89 33.37 12.36
9 18% in foil 31.11 29.48 12.31
14 12% in foil 36.99 35.59 13.20
17 14% in foil 35.21 33.93 14.10
1 20% exposed 32.48 31.33 13.78
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
9 18% exposed 32.21 31.05 13.34
14 12% exposed 32.01 30.85 13.26
17 14% exposed 32.30 31.19 13.56
1 50% exposed 28.56 26.95 10.11
9 50% exposed 28.45 26.90 10.74
14 50% exposed 28.14 26.57 10.22
17 50% exposed 27.56 26.15 11.24
Example 11-16
Samples were prepared in same way as Example II-1, except the silver nitrate
solution was prepared by placing 0.632 g silver nitrate and 200 g distilled
water in a glass
bottle. This resulting silver nitrate solution was approximately 2000 g Ag/g.
The color
of the samples was off-white. The results from color monitoring experiments
are shown in
Table II-16.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1516 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 10.6 mg silver ion
per gram of
sample within 30 minutes of placing the sample in 98 grams distilled water and
2.96
grams of 5M sodium nitrate. By comparison, a 0.1368 g sample that was kept in
foil
during the 168 hours released 12.4 mg of silver ion per gram of sample into 98
grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
14000 mg Ag/kg sample. The silver metal content was 800 mg/kg sample.
TABLE II-16. Example II-16 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 75.30 76.89 77.09
2 12% in foil 75.53 77.17 77.28
4 11% in foil 75.87 77.46 77.74
8 12% in foil 75.16 76.77 77.10
56
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
24 11% in foil 76.30 77.97 78.73
48 10% in foil 75.58 77.21 77.59
120 16% in foil 75.33 76.89 77.04
168 18% in foil 75.80 77.43 77.55
0 12% exposed 78.27 79.89 77.61
2 12% exposed 78.33 80.04 79.92
4 11% exposed 78.53 80.12 79.39
8 12% exposed 79.66 81.14 80.07
24 11% exposed 74.36 75.23 71.10
48 10% exposed 73.10 73.56 70.26
120 16% exposed 58.89 59.01 52.31
168 18% exposed 52.66 52.83 45.66
0 49% exposed 74.12 75.65 75.08
2 49% exposed 72.31 73.65 71.54
4 49% exposed 70.98 71.96 69.21
8 48% exposed 67.24 67.78 64.11
24 47% exposed 52.12 52.61 49.25
48 47% exposed 38.39 39.49 36.00
120 47% exposed 25.21 25.63 19.53
168 47% exposed 22.44 22.83 16.78
Example 11-17
Samples were prepared in same way as Example II-1, except the silver nitrate
solution was prepared by placing 1.261 g silver nitrate and 200 g distilled
water in a glass
bottle. This resulting silver nitrate solution was approximately 4000
micrograms ( g) Ag
per gram (g). The color of the samples was initially off-white and developed
gray areas
(splotchy) upon exposure to light. The results from color monitoring
experiments are
shown in Table II-17.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1360 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 35.35 mg silver ion
per gram
57
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
of sample within 30 minutes of placing the sample in 98 grams distilled water
and 2.96
grams of 5M sodium nitrate. By comparison, a 0.1211 g sample that was kept in
foil
during the 168 hours released 27.37 mg of silver ion per gram of sample into
98 grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
28,500 mg Ag/kg sample. The silver metal content was 1400 mg/kg sample.
TABLE II-17. Example II-17 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 73.87 75.46 77.48
2 12% in foil 74.13 75.74 73.98
4 11% in foil 73.94 75.51 73.60
8 12% in foil 74.10 75.70 74.11
24 11% in foil 72.79 74.40 72.92
48 10% in foil 73.89 75.53 74.38
120 16% in foil 73.97 75.47 73.60
168 18% in foil 73.62 75.24 73.63
0 12% exposed 78.92 80.55 78.70
2 12% exposed 78.39 79.88 78.74
4 11% exposed 77.15 78.53 78.78
8 12% exposed 75.16 76.30 76.56
24 11% exposed 70.52 70.80 68.93
48 10% exposed 61.48 61.39 61.30
120 16% exposed 48.40 48.93 48.63
168 18% exposed 40.41 41.29 38.73
0 49% exposed 70.91 72.59 72.84
2 49% exposed 68.15 69.45 64.16
4 49% exposed 66.20 67.07 61.32
8 48% exposed 59.62 59.83 54.12
24 47% exposed 39.81 40.26 36.05
58
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
48 47% exposed 29.03 29.81 25.12
120 47% exposed 13.65 13.63 9.97
168 47% exposed 11.48 11.34 8.12
Example 11-18
Samples were prepared in same way as Example II-16, except the drying
temperature was 130 C. The color of the samples was light yellow. The results
from
color monitoring experiments are shown in Table II-18.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1423 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 14.81 mg silver ion
per gram
of sample within 30 minutes of placing the sample in 98 grams distilled water
and 2.96
grams of 5M sodium nitrate. By comparison, a 0.1411 g sample that was kept in
foil
during the 168 hours released 10.36 mg of silver ion per gram of sample into
98 grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
13,000 mg Ag/kg sample. The silver metal content was 970 mg/kg sample.
TABLE II-18. Example II-18 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 52.98 52.55 33.91
2 12% in foil 53.68 53.29 34.27
4 11% in foil 53.97 53.62 34.95
8 12% in foil 53.93 53.55 34.48
24 11% in foil 54.27 53.95 34.88
48 10% in foil 54.07 53.70 34.80
120 16% in foil 53.75 53.48 34.58
168 18% in foil 54.24 53.96 35.00
0 12% exposed 50.45 49.86 32.06
2 12% exposed 50.71 50.18 32.60
59
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
4 11% exposed 50.68 50.08 31.95
8 12% exposed 50.91 50.25 31.91
24 11% exposed 49.39 48.48 30.70
48 10% exposed 45.79 44.69 28.71
120 16% exposed 39.41 38.17 24.11
168 18% exposed 33.36 32.65 22.80
0 49% exposed 53.06 52.68 33.77
2 49% exposed 53.01 52.53 32.24
4 49% exposed 52.24 51.67 31.74
8 48% exposed 50.41 49.52 29.69
24 47% exposed 40.06 39.17 24.68
48 47% exposed 31.50 31.52 20.68
120 47% exposed 21.56 21.28 13.80
168 47% exposed 19.77 19.22 12.06
Example 11-19
Samples were prepared in same way as Example II-17, except the drying
temperature was 130 C. The color of the samples was non-uniform in that it was
light
yellow that contained irregular areas of gray/black giving it a slightly
mottled appearance.
The results from color monitoring experiments are shown in Table II-19.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1176 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 35.25 mg silver ion
per gram
of sample within 30 minutes of placing the sample in 98 grams distilled water
and 2.96
grams of 5M sodium nitrate. By comparison, a 0.1313 g sample that was kept in
foil
during the 168 hours released 24.93 mg of silver ion per gram of sample into
98 grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
28,000 mg Ag/kg sample. The silver metal content was 1500 mg/kg sample.
TABLE II-19. Example II-19 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 51.51 51.71 35.49
2 12% in foil 50.74 51.04 35.16
4 11% in foil 52.00 52.29 35.94
8 12% in foil 51.99 52.35 36.25
24 11% in foil 51.20 51.50 35.58
48 10% in foil 52.60 53.00 36.81
120 16% in foil 50.97 51.30 35.56
168 18% in foil 52.41 52.82 36.30
0 12% exposed 50.84 50.82 35.60
2 12% exposed 51.31 51.21 35.54
4 11% exposed 50.89 50.89 35.24
8 12% exposed 51.18 51.01 35.12
24 11% exposed 48.48 48.39 34.79
48 10% exposed 47.16 46.46 31.66
120 16% exposed 39.85 39.05 27.42
168 18% exposed 35.81 35.16 23.92
0 49% exposed 49.81 49.68 33.88
2 49% exposed 49.12 48.88 31.87
4 49% exposed 48.67 48.29 31.3
8 48% exposed 46.65 46.07 29.81
24 47% exposed 37.12 36.61 24.49
48 47% exposed 29.08 28.96 19.63
120 47% exposed 21.56 21.28 13.80
168 47% exposed 19.77 19.22 12.06
Example 11-20
Samples were prepared in same way as Example II-19, except the drying
temperature was 155 C. The color of the samples was non-uniform in that it was
a darker
61
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
golden yellow on one side by comparison to the other side. The lighter side
was tested for
color and those results are shown in Table 11-20.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1358 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 26.32 mg silver ion
per gram
of sample within 30 minutes of placing the sample in 98 grams distilled water
and 2.96
grams of 5M sodium nitrate. By comparison, a 0.1395 g sample that was kept in
foil
during the 168 hours released 18.21 mg of silver ion per gram of sample into
98 grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
27,500 mg Ag/kg sample. The silver metal content was 3100 mg/kg sample.
TABLE 11-20. Example 11-20 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 37.03 36.21 17.70
2 12% in foil 37.95 37.09 17.57
4 11% in foil 37.08 36.22 17.62
8 12% in foil 37.19 36.31 17.84
24 11% in foil 37.41 36.57 17.89
48 10% in foil 37.49 36.66 17.89
120 16% in foil 37.77 36.96 18.29
168 18% in foil 37.96 37.19 18.36
0 12% exposed 36.99 35.89 17.15
2 12% exposed 37.00 35.89 17.66
4 11% exposed 37.10 36.02 17.63
8 12% exposed 37.45 36.22 16.96
24 11% exposed 36.27 35.08 17.48
48 10% exposed 36.04 34.73 16.60
120 16% exposed 34.11 32.62 15.21
168 18% exposed 32.21 30.61 14.38
62
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
0 49% exposed 38.82 38.1 19.16
2 49% exposed 39.06 38.42 18.93
4 49% exposed 38.71 38.04 18.97
8 48% exposed 37.95 37.13 18.08
24 47% exposed 36.74 35.63 16.78
48 47% exposed 32.61 31.27 14.58
120 47% exposed 23.56 21.15 9.79
168 47% exposed 19.31 16.92 8.47
Example II-21
Samples were prepared in same way as Example II-1, except the drying
temperature was 180 C. The color of the samples was golden yellow. The results
from
color monitoring experiments are shown in Table II-21.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1405 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 0.10 mg silver ion
per gram of
sample within 30 minutes of placing the sample in 98 grams distilled water and
2.96
grams of 5M sodium nitrate. By comparison, a 0.1371 g sample that was kept in
foil
during the 168 hours released 0.52 mg of silver ion per gram of sample into 98
grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
1850 mg Ag/kg sample. The silver metal content was 450 mg/kg sample.
TABLE II-21. Example 11-21 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 50.36 50.05 20.82
2 12% in foil 51.67 51.46 21.91
4 11% in foil 49.33 48.86 20.45
8 12% in foil 49.29 48.79 20.46
24 11% in foil 49.98 49.52 20.58
63
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
48 10% in foil 50.08 49.59 20.57
120 16% in foil 49.38 48.71 20.35
168 18% in foil 49.74 49.16 20.33
0 12% exposed 52.53 52.7 24.77
2 12% exposed 52.67 52.83 24.91
4 11% exposed 52.89 53.06 25.05
8 12% exposed 52.51 52.66 24.93
24 11% exposed 52.61 52.73 25.15
48 10% exposed 52.36 52.42 25.14
120 16% exposed 51.86 51.9 25.09
168 18% exposed 50.87 50.94 24.79
0 49% exposed 48.59 48.20 20.93
2 49% exposed 47.66 46.93 19.51
4 49% exposed 47.71 47.03 19.80
8 48% exposed 46.40 45.63 18.90
24 47% exposed 46.19 45.48 19.32
48 47% exposed 43.95 43.16 18.58
120 47% exposed 41.76 41.21 18.86
168 47% exposed 40.21 29.71 18.06
Example 11-22
Samples were prepared in same way as Example II-16, except the drying
temperature was 180 C. The color of the samples was dark golden yellow. The
results
from color monitoring experiments are shown in Table 11-22.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1364 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 0.80 mg silver ion
per gram of
sample within 30 minutes of placing the sample in 98 grams distilled water and
2.96
grams of 5M sodium nitrate. By comparison, a 0.1340 g sample that was kept in
foil
during the 168 hours released 1.88 mg of silver ion per gram of sample into 98
grams of
64
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
16000 mg Ag/kg sample. The silver metal content was 2700 mg/kg sample.
TABLE 11-22. Example 11-22 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 24.67 23.32 10.12
2 12% in foil 24.74 23.36 10.25
4 11% in foil 24.53 23.01 8.67
8 12% in foil 24.89 23.48 10.08
24 11% in foil 25.33 23.94 10.77
48 10% in foil 25.27 23.77 10.58
120 16% in foil 25.43 23.92 10.47
168 18% in foil 25.01 23.45 10.15
0 12% exposed 21.93 20.16 8.52
2 12% exposed 21.38 20.13 8.75
4 11% exposed 20.28 18.97 8.62
8 12% exposed 19.67 18.37 8.31
24 11% exposed 19.97 18.6 8.09
48 10% exposed 19.89 18.52 8.11
120 16% exposed 18.76 17.38 7.46
168 18% exposed 19.21 17.93 8.42
0 49% exposed 25.39 24.21 8.56
2 49% exposed 27.09 25.73 8.55
4 49% exposed 26.13 24.77 8.20
8 48% exposed 25.32 23.98 8.15
24 47% exposed 25.71 24.47 8.26
48 47% exposed 23.98 22.67 8.03
120 47% exposed 26.62 25.52 8.75
168 47% exposed 26.23 25.16 8.86
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
Example 11-23
Samples were prepared in same way as Example II-17, except the drying
temperature was 180 C. The color of the samples was dark brown with black
portions
giving it the appearance of a burnt brown color. The results from color
monitoring
experiments are shown in Table 11-23.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1443 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 1.50 mg silver ion
per gram of
sample within 30 minutes of placing the sample in 98 grams distilled water and
2.96
grams of 5M sodium nitrate. By comparison, a 0.1496 g sample that was kept in
foil
during the 168 hours released 3.30 mg of silver ion per gram of sample into 98
grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
27500 mg Ag/kg sample. The silver metal content was 7500 mg/kg sample.
TABLE 11-23. Example 11-23 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 15.23 14.06 8.20
2 12% in foil 14.81 13.56 7.38
4 11% in foil 15.30 14.00 7.72
8 12% in foil 15.28 13.97 7.64
24 11% in foil 15.48 14.19 8.01
48 10% in foil 15.42 14.16 8.22
120 16% in foil 15.24 13.88 7.51
168 18% in foil 15.61 14.30 8.13
0 12% exposed 14.32 13.09 6.35
2 12% exposed 15.14 13.96 7.40
4 11% exposed 15.02 13.89 8.06
8 12% exposed 15.05 13.82 7.27
24 11% exposed 15.25 14.03 7.40
66
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
48 10% exposed 14.37 13.29 8.21
120 16% exposed 15.14 13.90 7.02
168 18% exposed 14.63 13.54 7.64
0 49% exposed 15.16 13.88 7.12
2 49% exposed 14.98 13.57 6.67
4 49% exposed 15.07 13.63 6.48
8 48% exposed 15.90 14.46 7.15
24 47% exposed 15.75 14.41 7.29
48 47% exposed 14.94 13.64 6.67
120 47% exposed 15.12 13.86 7.18
168 47% exposed 14.30 13.03 6.45
Example 11-24
Samples were prepared in same way as Example II-10, except the drying
temperature was 130 C. The color of the samples was light yellow. The results
from
color monitoring experiments are shown in Table 11-24.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1385 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 0.84 mg silver ion
per gram of
sample within 30 minutes of placing the sample in 98 grams distilled water and
2.96
grams of 5M sodium nitrate. By comparison, a 0.1286 g sample that was kept in
foil
during the 168 hours released 1.93 mg of silver ion per gram of sample into 98
grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
3750 mg Ag/kg sample.
TABLE 11-24. Example 11-24 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 49.48 48.61 29.17
2 12% in foil 49.51 48.61 29.56
67
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
4 11% in foil 49.87 48.99 29.80
8 12% in foil 49.47 48.55 29.76
24 11% in foil 49.55 48.55 29.99
48 10% in foil 49.65 48.72 29.84
120 16% in foil 49.56 48.57 30.69
168 18% in foil 49.92 49.02 30.48
0 12% exposed 53.26 52.83 34.06
2 12% exposed 53.38 52.95 34.29
4 11% exposed 52.99 52.62 33.81
8 12% exposed 52.60 52.34 33.43
24 11% exposed 51.75 51.51 32.31
48 10% exposed 51.74 51.48 32.42
120 16% exposed 50.66 50.08 29.90
168 18% exposed 48.19 47.37 26.87
0 49% exposed 50.77 50.14 31.19
2 49% exposed 49.79 48.88 29.28
4 49% exposed 49.91 48.91 29.29
8 48% exposed 49.92 48.88 28.65
24 47% exposed 46.59 45.05 26.48
48 47% exposed 43.36 42.00 24.19
120 47% exposed 35.83 34.86 20.96
168 47% exposed 35.53 34.47 20.33
Example 11-25
Samples were prepared in same way as Example II-11, except the drying
temperature was 130 C. The color of the samples was yellow tan. The results
from color
monitoring experiments are shown in Table 11-25.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1377 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 3.14 mg silver ion
per gram of
sample within 30 minutes of placing the sample in 98 grams distilled water and
2.96
68
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
grams of 5M sodium nitrate. By comparison, a 0.1540 g sample that was kept in
foil
during the 168 hours released 4.01 mg of silver ion per gram of sample into 98
grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
6850 mg Ag/kg sample.
TABLE 11-25. Example 11-25 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 40.28 38.41 20.89
2 12% in foil 40.30 38.40 20.89
4 11% in foil 40.49 38.61 21.11
8 12% in foil 40.58 38.68 21.09
24 11% in foil 40.40 38.53 21.16
48 10% in foil 40.70 38.81 21.25
120 16% in foil 40.77 38.93 21.35
168 18% in foil 40.95 39.12 21.51
0 12% exposed 37.92 35.71 19.87
2 12% exposed 37.55 35.41 19.68
4 11% exposed 37.83 35.7 20.14
8 12% exposed 37.38 35.33 20.07
24 11% exposed 36.37 34.48 19.59
48 10% exposed 35.85 33.92 19.08
120 16% exposed 34.22 32.05 18.15
168 18% exposed 32.83 30.7 16.99
0 49% exposed 41.09 39.20 21.26
2 49% exposed 40.12 37.98 19.59
4 49% exposed 39.82 37.54 19.26
8 48% exposed 39.04 36.71 18.93
24 47% exposed 37.79 35.21 17.71
48 47% exposed 34.82 32.16 16.40
69
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
120 47% exposed 26.52 24.84 13.52
168 47% exposed 28.89 23.58 13.31
Example 11-26
Samples were prepared in same way as Example 11-8, except the substrate was a
non-woven of 100% TENCEL fibers (SX-152, white, 65 gsm, 24 mesh, from Green
Bay
Nonwovens, Inc. in Green Bay, WI) that contained less than 40 ppm chloride.
The color
of the samples was golden yellow. The results from color monitoring
experiments are
shown in Table 11-26.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1902 g of the sample that was
exposed to light
for 168 hr at approximately 20% relative humidity released 2.19 mg silver ion
per gram of
sample within 30 minutes of placing the sample in 98 grams distilled water and
2.96
grams of 5M sodium nitrate. By comparison, a 0.1931 g sample that was kept in
foil
during the 168 hours released 2.87 mg of silver ion per gram of sample into 98
grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
7350 mg Ag/kg sample.
TABLE 11-26. Example 11-26 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 25.87 23.52 6.56
2 12% in foil 26.24 23.87 6.69
4 11% in foil 26.43 24.05 6.76
8 12% in foil 26.11 23.77 6.70
24 11% in foil 26.08 23.74 6.77
48 10% in foil 26.45 24.06 6.71
120 16% in foil 26.61 24.20 6.70
168 18% in foil 26.97 24.50 6.69
0 12% exposed 26.29 23.91 7.06
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
2 12% exposed 25.01 22.67 6.35
4 11% exposed 25.43 23.19 6.76
8 12% exposed 25.79 23.57 7.01
24 11% exposed 24.65 22.66 6.75
48 10% exposed 24.02 22.24 6.90
120 16% exposed 21.62 20.28 6.62
168 18% exposed 21.35 20.19 6.89
0 49% exposed 26.03 23.70 6.96
2 49% exposed 25.31 23.24 6.65
4 49% exposed 24.56 22.73 6.79
8 48% exposed 23.39 21.83 6.82
24 47% exposed 21.17 20.31 7.38
48 47% exposed 19.46 19.15 7.82
120 47% exposed 18.81 18.93 9.41
168 47% exposed 19.06 19.30 10.53
Example 11-27
Samples were prepared in same way as Example 11-8, except the substrate was a
non-woven of 70% LYOCELL fibers/30% PET (SX-156, white, 50 gsm, FT-10
apertured,
from Ahlstrom Green Bay, Inc. in Green Bay, WI) that contained less than 40
ppm
chloride. The color of the samples was golden yellow. The results from color
monitoring
experiments are shown in Table 11-27.
Silver ion release and total silver content measurements were conducted as
described in Example II-1. An amount of 0.1608 g of the sample that was
exposed to light
for 168 hours (hr) at approximately 20% relative humidity released 2.99 mg
silver ion per
gram of sample within 30 minutes of placing the sample in 98 grams distilled
water and
2.96 grams of 5M sodium nitrate. By comparison, a 0.1515 g sample that was
kept in foil
during the 168 hours released 6.53 mg of silver ion per gram of sample into 98
grams of
distilled water and 2.96 grams of sodium nitrate. The average total silver
content was
8450 mg Ag/kg sample.
TABLE 11-27. Example 11-27 Color with Time
71
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 12% in foil 37.89 36.07 13.51
2 12% in foil 38.35 36.52 13.90
4 11% in foil 38.39 36.59 13.97
8 12% in foil 37.93 36.11 13.38
24 11% in foil 38.47 36.66 13.93
48 10% in foil 38.01 36.15 13.20
120 16% in foil 38.91 37.08 14.10
168 18% in foil 39.18 37.33 14.01
0 12% exposed 39.10 37.42 14.55
2 12% exposed 35.30 34.09 14.17
4 11% exposed 34.49 33.64 14.74
8 12% exposed 31.97 31.33 13.88
24 11% exposed 29.08 28.92 13.94
48 10% exposed 25.77 25.81 13.32
120 16% exposed 22.25 22.60 12.58
168 18% exposed 20.82 21.41 13.62
0 49% exposed 39.77 38.03 15.23
2 49% exposed 34.17 33.34 15.14
4 49% exposed 29.05 28.56 13.57
8 48% exposed 26.53 26.61 14.47
24 47% exposed 22.57 23.18 15.47
48 47% exposed 22.06 22.72 17.23
120 47% exposed 20.75 21.17 17.60
168 47% exposed 22.96 23.32 20.73
72
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
Example 11-28 (Comparative)
Samples were prepared in same way as Example 11-4, except the drying
temperature was 80 C. The initial color of the samples was off white. The
results from
color monitoring experiments are shown in Table 11-28.
TABLE 11-28. Example 11-28 (Comparative) Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 28% in foil 90.11 92.05 103.38
2 28% in foil 88.36 90.24 100.54
4 28% in foil 89.33 91.28 101.61
8 28% in foil 89.45 91.36 101.37
24 28% in foil 87.69 89.60 98.82
0 28% exposed 89.91 91.83 102.77
2 28% exposed 81.82 82.87 91.87
4 28% exposed 74.05 74.31 81.64
8 28% exposed 64.83 64.22 67.01
24 28% exposed 44.04 43.82 45.43
0 50% exposed 91.11 93.06 105.01
2 50% exposed 84.35 85.39 94.23
4 50% exposed 76.12 76.24 81.43
8 50% exposed 57.88 56.99 57.51
24 50% exposed 36.17 36.59 35.92
Example 11-29 (Comparative)
Samples were prepared in same way as Example II-11, except the drying
temperature was 80 C. The initial color of the samples was off white. The
results from
color monitoring experiments are shown in Table 11-29.
TABLE 11-29. Example 11-29 (Comparative) Color with Time
73
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 28% in foil 88.51 90.40 98.82
2 28% in foil 87.96 89.84 97.60
4 28% in foil 88.26 90.13 97.57
8 28% in foil 88.29 90.18 97.03
24 28% in foil 86.37 88.27 93.35
0 28% exposed 90.06 91.99 102.55
2 28% exposed 86.96 88.49 97.45
4 28% exposed 83.47 84.56 92.26
8 28% exposed 75.28 75.27 79.70
24 28% exposed 54.60 54.14 56.55
0 50% exposed 88.58 90.47 99.23
2 50% exposed 82.85 83.98 90.29
4 50% exposed 75.59 75.77 81.13
8 50% exposed 60.09 59.35 62.85
24 50% exposed 34.42 35.74 37.87
Example 11-30 (Comparative)
Samples were prepared in same way as Example 11-28, except the substrate was a
non-woven of 70% Viscose/30% PET fibers (507030RPET P1, white, 50 gsm, from FA-
MA JERSEY S.p.A. of Italy). The initial color of the samples was off white.
The results
from color monitoring experiments are shown in Table 11-30.
TABLE 11-30. Example 11-30 (Comparative) Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
X Y Z
(hr) (%RH)
0 28% in foil 81.37 82.74 86.19
2 28% in foil 80.15 81.31 84.22
74
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
4 28% in foil 81.30 82.52 86.23
8 28% in foil 80.10 81.18 84.08
24 28% in foil 78.68 79.73 82.21
0 28% exposed 84.09 85.69 90.95
2 28% exposed 40.47 41.03 45.52
4 28% exposed 34.16 34.53 38.44
8 28% exposed 27.04 27.02 29.61
24 28% exposed 22.53 22.32 23.17
0 50% exposed 83.47 84.96 88.89
2 50% exposed 36.60 36.75 40.03
4 50% exposed 30.65 30.61 33.06
8 50% exposed 24.80 24.51 24.75
24 50% exposed 19.87 19.56 16.79
Example 11-31 (Comparative)
Samples were prepared in same way as Example 11-29, except the substrate was a
non-woven of 70% Viscose/30% PET fibers (507030RPET P1, white, 50 gsm, from FA-
MA JERSEY S.p.A. of Italy). The initial color of the samples was off white.
The results
from color monitoring experiments are shown in Table II-31.
TABLE II-31. Example 11-31 (Comparative) Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
X Y Z
(hr) (%RH)
0 28% in foil 83.81 85.50 89.18
2 28% in foil 83.26 84.89 88.50
4 28% in foil 83.92 85.59 89.66
8 28% in foil 82.67 84.25 87.58
24 28% in foil 81.72 83.42 86.21
0 28% exposed 85.94 87.80 92.68
2 28% exposed 50.71 51.40 58.32
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
4 28% exposed 42.69 43.07 48.42
8 28% exposed 32.40 31.80 33.98
24 28% exposed 24.65 24.29 24.94
0 50% exposed 84.83 86.65 90.38
2 50% exposed 45.73 46.53 51.53
4 50% exposed 37.08 37.04 39.38
8 50% exposed 28.42 27.50 26.63
24 50% exposed 19.13 17.95 14.25
Example 11-32 (Comparative)
Samples were prepared in same way as Example 11-27, except the drying
temperature was 80 C. The initial color of the samples was off white. The
results from
color monitoring experiments are shown in Table 11-32.
TABLE 11-32. Example 11-32 (Comparative) Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 28% in foil 82.78 83.66 90.59
2 28% in foil 82.40 83.23 90.07
4 28% in foil 82.70 83.49 90.27
8 28% in foil 82.50 83.21 89.90
24 28% in foil 80.46 81.05 87.50
0 28% exposed 84.02 85.04 91.42
2 28% exposed 41.48 41.60 46.75
4 28% exposed 32.67 32.97 38.11
8 28% exposed 28.61 29.01 33.61
24 28% exposed 23.99 24.36 28.34
0 50% exposed 84.96 86.10 93.01
2 50% exposed 40.73 40.84 46.51
4 50% exposed 33.88 34.04 39.12
76
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
8 50% exposed 29.17 29.43 33.70
24 50% exposed 25.38 25.52 27.80
Example 11-33
Samples were prepared in same way as Example 11-30, except the drying
temperature was 155 C. The initial color of the samples was golden brown. The
results
from color monitoring experiments are shown in Table 11-33.
TABLE II-33. Example II-33 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 28% in foil 26.03 24.03 9.53
2 28% in foil 25.72 23.77 9.42
4 28% in foil 25.69 23.77 9.46
8 28% in foil 25.77 23.87 9.16
24 28% in foil 26.48 24.47 9.62
0 28% exposed 27.95 25.92 8.87
2 28% exposed 25.83 24.13 8.88
4 28% exposed 24.13 22.58 8.67
8 28% exposed 21.78 20.62 8.59
24 28% exposed 18.66 18.03 8.31
0 50% exposed 25.77 23.92 8.58
2 50% exposed 24.15 22.54 8.41
4 50% exposed 22.97 21.47 8.38
8 50% exposed 20.79 19.59 8.18
24 50% exposed 17.63 16.97 7.64
77
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
Example 11-34
Samples were prepared in same way as Example II-31, except the drying
temperature was 155 C. The initial color of the samples was golden brown. The
results
from color monitoring experiments are shown in Table 11-34.
TABLE 11-34. Example II-34 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 28% in foil 27.80 26.40 11.98
2 28% in foil 28.41 27.00 12.17
4 28% in foil 28.37 26.96 12.06
8 28% in foil 28.07 26.65 11.88
24 28% in foil 28.05 26.61 11.91
0 28% exposed 29.39 28.01 13.29
2 28% exposed 28.68 27.36 13.17
4 28% exposed 28.93 27.67 13.44
8 28% exposed 27.55 26.33 12.96
24 28% exposed 26.04 24.83 12.44
0 50% exposed 29.57 28.45 12.61
2 50% exposed 27.29 26.42 12.20
4 50% exposed 25.72 24.96 11.72
8 50% exposed 24.79 24.21 12.14
24 50% exposed 22.14 22.01 11.44
Example 11-35
Samples were prepared in same way as Example 11-8, except the substrate was
woven nylon fibers (SR-823-32x28, 60 gsm, from American Fiber and Finishing in
Albemarle, NC). The initial color of the samples was brown. The results from
color
monitoring experiments are shown in Table 11-35.
TABLE II-35. Example II-35 Color with Time
78
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 28% in foil 48.45 48.01 40.25
2 28% in foil 47.78 47.23 39.54
4 28% in foil 49.45 48.98 41.26
8 28% in foil 51.37 51.02 43.06
24 28% in foil 49.61 49.19 41.67
0 28% exposed 45.29 44.93 39.33
2 28% exposed 46.72 46.56 42.18
4 28% exposed 44.99 44.80 40.59
8 28% exposed 44.05 43.65 38.92
24 28% exposed 42.50 42.01 37.52
0 50% exposed 46.14 46.01 39.51
2 50% exposed 58.75 59.19 56.32
4 50% exposed 56.22 56.55 53.54
8 50% exposed 47.25 47.12 42.27
24 50% exposed 50.58 50.64 47.74
Example 11-36
Samples were prepared in same way as Example II-11, except the substrate was
woven nylon fibers (SR-823-32x28, 60 gsm, from American Fiber and Finishing in
Albemarle, NC). The initial color of the samples was brown. The results from
color
monitoring experiments are shown in Table 11-36.
TABLE II-36. Example II-36 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 28% in foil 36.27 35.64 27.31
2 28% in foil 44.44 44.49 37.32
79
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
4 28% in foil 35.03 34.84 29.53
8 28% in foil 36.56 36.33 30.93
24 28% in foil 33.35 33.65 28.49
0 28% exposed 35.83 35.60 28.67
2 28% exposed 35.22 34.94 28.33
4 28% exposed 33.89 33.51 27.10
8 28% exposed 34.26 33.96 28.05
24 28% exposed 33.22 32.93 27.19
0 50% exposed 31.39 31.09 25.81
2 50% exposed 32.89 32.53 27.09
4 50% exposed 32.20 31.88 26.69
8 50% exposed 32.22 31.92 27.21
24 50% exposed 29.86 29.55 25.23
Example 11-37
Samples were prepared in same way as Example 11-8, except the substrate was a
membrane filter comprised of cellulose nitrate and cellulose acetate (0.22 M
filters,
GSWP 047 00, available from Millipore in Billerica, MA). The initial color of
the
samples was light brown. The results from color monitoring experiments are
shown in
Table II-37.
TABLE II-37. Example II-37 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 28% in foil 52.70 53.08 43.49
2 28% in foil 50.38 50.72 41.49
4 28% in foil 53.88 54.26 44.62
8 28% in foil 50.92 51.35 41.98
24 28% in foil 48.23 48.58 39.78
0 28% exposed 47.75 48.06 41.09
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
2 28% exposed 47.95 48.23 40.67
4 28% exposed 46.68 46.97 39.67
8 28% exposed 48.14 48.36 40.63
24 28% exposed 47.60 47.90 40.14
0 50% exposed 35.99 35.72 29.34
2 50% exposed 37.17 36.71 30.12
4 50% exposed 35.95 35.53 29.08
8 50% exposed 40.81 40.07 32.55
24 50% exposed 34.63 34.17 27.51
Example 11-38
Samples were prepared in same way as Example II-11, except the substrate was a
membrane filter comprised of cellulose nitrate and cellulose acetate (0.22 M
filters,
GSWP 047 00, available from Millipore in Billerica, MA). The initial color of
the
samples was light brown. The results from color monitoring experiments are
shown in
Table 11-3 8.
TABLE II-38. Example II-38 Color with Time
Exposure Relative Exposure CIE Tristimulus Values
Time Humidity conditions
x y z
(hr) (%RH)
0 28% in foil 48.08 48.44 46.63
2 28% in foil 46.75 47.11 45.86
4 28% in foil 44.59 44.96 45.32
8 28% in foil 46.32 46.63 45.72
24 28% in foil 44.24 44.58 44.62
0 28% exposed 57.66 57.96 55.63
2 28% exposed 55.49 55.78 53.51
4 28% exposed 56.39 56.66 54.42
8 28% exposed 52.69 52.98 51.03
24 28% exposed 53.82 54.07 52.28
81
CA 02666826 2009-04-17
WO 2008/060795 PCT/US2007/081477
0 50% exposed 53.64 53.91 50.99
2 50% exposed 46.59 46.92 45.26
4 50% exposed 51.65 51.91 49.15
8 50% exposed 52.03 52.34 49.42
24 50% exposed 50.82 51.14 48.69
The complete disclosures of the patents, patent documents, and publications
cited
herein are incorporated by reference in their entirety as if each were
individually
incorporated. Various modifications and alterations to this invention will
become
apparent to those skilled in the art without departing from the scope and
spirit of this
invention. It should be understood that this invention is not intended to be
unduly limited
by the illustrative embodiments and examples set forth herein and that such
examples and
embodiments are presented by way of example only with the scope of the
invention
intended to be limited only by the claims set forth herein as follows.
82
