Note: Descriptions are shown in the official language in which they were submitted.
~23~()6~3
BLP:l04
MICROBIAL ENZYMATIC CONTACT LEWIS CLIP
AND METHODS OF USE
BACKGROUND OF THE INVENTION
..
The present invention relates generally to lens
cleaning compositions and methods of use, More
specifically, this invention is concerned with new enzyme
cleaners and methods for effective removal of film build-
up and debris from contact lenses which may be present asproteinaceous-carbohydrate-lipid containing deposits.
Cleaning compositions for contact lenses generally
fall into one of three categories: surfactant cleaners;
oxidative cleaners and enzyme cleaners. Surfactant
cleaners are widely used, for example, by placing a drop
of solution on a lens, rubbing the lens between the
fingers followed by rinsing. Although such cleaners are
usually safe and not harmful to lenses when used properly,
most surfactan~ cleaners are not effective in the removal
of protein deposits.
The second type of cleaning system involves oxidative
products containing, for example, per sulfates and
perorates. They may be used either by cold soaking or
with boiling for about 30 minutes. This type type of
cleaning system is mainly effective in removing non-
protein deposits from contact lenses. They are generally
non-toxic, however, oxidizing agents can have a
deleterious effect on lenses. One possible explanation
is that they may oxidize the basic polymer chain by the
introduction of pH-sensitive molecular groups.
The third method of cleaning is with enzymes.
Enzyme cleaners are generally viewed as being efficacious,
safe and capable of removing the principal component of
contact lens film and debris, namely protein. Some also
have the ability to remove carbohydrate and lipid deposits
from contact lenses.
Heretofore, the supply of proteolytic, carbolytic and
lipolytic enzymes e.g.. pro teases, amylases and lapses
for use in contact lens cleaning solutions was restricted
to plant and animal sources. Cleaning solutions prepared
from plant and animal derived enzymes have several
lo shortcomings. In most instances, they either impart an
unpleasant odor to the cleaning bath or develop an odor
after a few hours of use. In some cases, plant and animal
pro teases and amylases will discolor lenses.
Contact lens cleaning solutions prepared with plant
15 and animal derived pro teases like pa pain, chymopapain,
pancreatic, trypsin, chymotrypsin, pepsin, ficin,
carboxypeptidase, aminopeptidase, and bromelin are
described in several patent publications e.g. USE.
Patent 3,910,296; US Patent Publication GO 2,088,581;
Japanese application 113,233 published May 31, 1975 as
Cook 64,303 and US. Patent 4,096,870. In addition to
the patent citations, enzymatic lens cleaners prepared
with pro teases from pork, namely pancreatic have been
commercially available from Alcoa Laboratories. Enzymatic
contact lens cleaners prepared with plant pro teases i.e.
pa pain have also been available from Allergen
Pharmaceuticals under the registered trademark Softens
Enzymatic Cleaning Tablets. Although these preparations
are generally effective in cleaning contact lenses, they
have shortcomings in addition to those previously
mint owned That is, besides the propensity for unpleasant
odors and potential for discoloring lenses, cleaners
containing pro teases like pancreatic from pork or beef can
induce an allergic response among some users. In
addition, solutions containing pancreatic have a tendency
I I
to become cloudy and turbid.
Plant pro teases for example Appian, normally require
lengthy cleaning cycles ranging from 4 to 12 hours in
order to remove film and debris from lenses. Such lengthy
cycles can be an inconvenience to the user. In addition,
cleaning solutions prepared with plant an animal
pro teases require the application of heat e.g. 80C which
is needed not only to disinfect the lenses, but also to
inactivate the enzyme.
lo contact lens cleaners containing enzymes also require
stabilizers/activators. For example, pa pain requires
Sistine. Pancreatic requires calcium salts. Without the
use of an activator pa pain and other similar plant enzymes
will remain dormant. Activators like Sistine are
hydroscopic and have a tendency to pick-up moisture
creating manufacturing difficulties. Such enzyme products
can only be manufactured and packaged under stringent
standards to eliminate any moisture from entering the
packaging otherwise it will attract and shorten the
shelf life of the cleaner.
Microbial rot eases derived from Bacillus and
Stratum bacteria and Aspergillus mold have been
previously described. US. Patent 3,590,121 discloses an
effervescent tablet used for making mouthwash. The
tablets and solutions of this patent employ a neutral
protozoa referred to as a metallo-enzyme having an optimum
activity at a pi of G to 8. Because metals are an
integral part of the enzyme, its activity is inhibited by
the presence of chelating agents which are customarily
employed in contact lens cleaning preparations to bind
calcium an other unwanted metals from reacting with
proteins and depositing on lenses. Consequently, enzymes
josh are inhibited by chelating agents, like those
described in US. 3,590,121 are generally unsatisfactory
123~ 69
for use with contact lenses.
US. 3,717,550 describes the preparation of liquid
concentrates of bacterial protozoa and/or aimless. The
liquid concentrates are used for making such products as
household detergents.
Accordingly, there is a need for safer, more
dependable enzyme cleaning preparations which will offer a
broad spectrum of cleaning capability for efficient
removal ox at least protein and carbohydrate films and
lo debris from contact lenses. The enzymes should be both
stable in solution, remain active at elevated
temperatures and be compatible with other components of
toe cleaning composition. Preferably, the enzyme system
should not depend on the use of activators which may lead
lo to auto digestion with the enzyme, limiting the shelf-
storage life. Similarly, the cleaning process should be
convenient for the user eliminating the need for
protracted soaking periods by allowing the user the
flexibility of shorter cleaning times. The enzyme
cleaning composition should also be free or substantially
free of odor and not cause discomfort to the wearer when
the lenses are reinserted into the eyes. They should not
cause irritation or allergic response as a result of
residual amounts of enzyme on the lens surface.
MARY OF THE INVASION
In accordance with this invention, there is provided
an enzymatic contact lens cleaner containing an effective,
non-toxic amount of a protozoa derived from a Bacillus,
Streptomyces or sprawls microorganism, such that when
mu dissolved in an aqueous solution will effectively remove
at least protein and carbohydrate films and debris from
contact lens surfaces. The enzyme cleaners may contain
protozoa alone derived from the above genera of bacteria
or mold. The enzyme will preferably be comprise of a
mixture predominantly of protozoa and aimless, and
optionally, a minor amount of Lopez.
This invention also contemplates various tablets
including effervescent and noneffervescent water soluble
tablets, including granules and powders which contain in
addition to the usual inert binders, excipients,
lubricants etc., other desirable functional additives,
like buffers, preservative, chelating agents, toxicity
adjusters, and the like, such that when dissolved in water
a preserved isotonic solution is formed and ready to be
used for lens cleaning. Similarly, the present invention
contemplates water-soluble microbial protease-amylase
tablets particularly suitable as heat unit enzyme tablets
for high temperature cleaning/disinfection of lenses. Such
tablets may be added to aqueous isotonic lens soaking or
cleaning solutions for cold soaking or high temperature
cleaning and disinfecting. These soaking and cleaning
solutions which the enzyme tablets are added to may
contain preservatives, chelating agents, surfactants, pal
buffers, toxicity adjusters, etc.
The microbial protease-containing lens cleaning
solutions are especially effective in digesting and
removing denatured protein and carbohydrate films and
debris from contact lenses without enzyme activators, and
therefore, present fewer Manufacturing and pacliaginO
problems in formulating the various cleaning preparations
contemplated herein.
The enzymatic contact lens cleaners of the present
invention are especially effective in removing contact
lens film and debris in one hour or less by high
temperature cleaning methods. In addition, the bacterial
enzyme cleaners may perform with little or no residual
binding or concentrating onto lens surfaces, and
therefore, eye tissue sensitivity normally manifested as
stinging and inflammation are virtually eliminated.
~L23~ 9
.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
This invention relates to cleaning solutions for use
with most contact lenses, including hard and 80ft lenses,
as well as the newer hard gas permeable type contact
lenses, such as described in US. patent 4,327,203. The
invention also relates to those soft lenses generally
referred to as extended-wear lenses containing 55 percent
or more water content. The term "soft contact lens" as
used herein generally refers to those contact lenses which
readily flex under small amounts of force and return to
their original shape when that force is released.
Typically, soft contact lenses are formulated from
poly(hydroxyethyl methacrylate) which has been in the
preferred formulations, cross-linked with ethylene glycol
dimethacrylate. For convenience, this polymer is
generally known as FUME. Soft contact lenses are also
made from silicon polymers cross-linked, for example, with
dim ethyl polysiloxane. Conventional "hard contact
lenses", which cover only the cornea of the eye, usually
consist of poly(methyl methacrylate) cross-linked with
ethylene luckily dimethacrylate.
The enzyme cleaners are derived from microorganisms
and include various species of Bacillus and Streptomyces
bacteria and Aspergillus mold. Species of microor~anisims
within the foregoing genera known to form mainly protozoa
and aimless are intended and include such members as B.
subtilis, B. licheniformis, As~er~illus ours,
._ _ _ _ _____ _ ______ __ __ _____ __ ___
Assyria us nicer, Stratum rises, StrePtomyces
Aryan. Protozoa and aimless derived from B- licheniformis
are generally preferred. The compositions herein may
contain only protozoa, but microbial enzymes in pure or
nearly pure form are not always readily available. Thus,
most commercially available products containing mixtures
lo )69
predominantly of protozoa and then aimless, including some
Lopez are satisfactory. The aimless is preferably I-
aimless because aimless it more sensitive to heat.
The microbial enzyme products contemplated herein
are commodities of commerce and are readily available from
a number of manufacturers under various designations. For
instance, Enzyme Development Corporation, Copyright, JOY
produces protozoa under the Enzeco trademark including a
food grade of protozoa, "PROTOZOA A I" derived from I.
lo licheniformis which also contains aimless activity. Finagle
protozoa produced from Asper~illus ours is also
available under the Enzeco trademark. Finagle protozoa is
also available from Corning BOO Systems, Corning, NAY.
under the Rhizome 41 trademark. Rhizome P-11 a protozoa
derived from AsPergillus flavus-oryzae is also available.
Protozoa under the Rhizome family of products include
those grades designated as B-6; PI; and P-53 produced from
By subtilis. Useful pro teases are also commercially
available from the International Enzyme Company, Nagoya,
Japan under the trademarks Amino; Prism and Nulls, and
from GOB. Fermentation Industries, Des Plainest Illinois
under the trademarks Maxatase and Prolate.
The protozoa should be active at a pi range of from
5 to about 8.5. The optimum riven pi for a given enzyme
product may be above or below this range. But, because of
the most preferred safe range for cleaning contact lenses
is about the neutral range the importance of proteolytic
activity in the highly alkaline and acidic pi ranges is
not critical.
Preferably, the protozoa should not be inhibited
when in the presence of a chelating agent, such as in the
case of metallo-enzymes.Protease activity according to
this invention may be expressed in cozen units and is
determined by the widely known procedure involving the
digestion of cozen. The procedure for assay of neutral
~LZ3~)6~3
protozoa activity it described in the Journal of General
Physiology, 30 (1947) 291 and Methods of Enzy~ology, 2,
Academic Press, New York 33 ~1955).
The enzymes preferably remain active when exposed to
elevated temperatures. That is to say, the methods
disclosed herein provide for cleaning lenses at ambient
temperature conditions using the "cold" soaking technique,
as well as elevated temperature conditions using high
temperature cleaning/disinfection methods.
The enzymatic cleaners containing mainly the protozoa
and aimless characterized hereinabove are employed in
amounts sufficient to digest and remove films and debris
from contact lenses. That is, the cleaning preparations
should contain sufficient enzyme activity that when
dissolved in the lens cleaning bath will remove virtually
all pretenses and carbohydrate debris and film by
either cold soaking or at elevated temperatures.
The enzyme concentration in solution will usually
range from about 0.0001 and 5.0% wlv. Enzyme tablet
preparations e.g. non-effervescent water soluble heat unit
tablets, effervescent tablets, granules or powder packets
will generally contain from about 0.01 to about 500 my of
enzyme, and more particularly, from about 10 to about 100
my of enzyme wherein the protozoa activity ranges from
about 30 to 80 cozen units/mg of enzyme, and more
preferably, about 40 to about 70 cozen units my of
enzyme.
As previously indicated, the present invention
contemplates various remeasured compositions as
convenient means for dispensing a sufficient amount of
enzyme for cleaning lenses. They include, for example,
soluble tablets which dissolve in aqueous solutions
without effervescing; effervescent tablets including
granules and powders each of which contain sufficient
~23~(~6g
composition for a jingle cleaning cycle. Also included
are large effervescent tablets which may be scored for
easy fracturing whereby each half tablet can be used in
making a cleaning solution for each lens placed in a lens
case.
In preparing powders and various tablets the enzyme
powder is formulated with known tablet binders or
excipients and may have inert carriers, disintegrants and
salts which will effervesce in aqueous solution. Methods
and materials for making such tablets and powders are all
well established practices in the tablet making art and
their identification and selection are matters of routine
skill.
In addition to the microbial enzymes, the tablets,
granules and powders may also be formulated with one or
more other ingredients to assure optimum cleaning activity
without adverse affects to the lens or to the users eyes.
For example, the enzyme preparations may contain a variety
of additives, such as toxicity adjusters, buy ens,
preservatives, surfactants, chelating agents to assure
stability and sterility of the cleaning solution, complete
dispersion of residual lipid deposits and the like.
Enzymatic cleaning tablets and powders containing such
complete formulations are highly convenient to the user,
since a cleaning solution can be prepared by simply
dissolving in distilled water. For example, tablets
granules and powders may be formulated with toxicity
agents to approximate the osmotic pressure of normal
lukewarmly fluids which is equivalent to a 0.9% solution of
sodium chloride or 2.5% glycerol solution.
It may also be advantageous to include a
disinfectant/germicide as a means for preserving the
cleaning solution. A preservative is added in sufficient
amount to provide a concentration in the cleaning bath
ranging from about 0.00001 to about 0.5 weight percent,
:~Z3~6~
and more preferably, from about 0.0001 to about 0.1 weight
percent. Suitable preservatives include, but are not
limited to thimerosal, sorbic acid, l,5-pentanedial, alkyd
triethanolamines, phenylmercuric salts, e.g. nitrate,
borate, acetate, chloride and mixtures thereof. Other
suitable compounds and salts may be used which are soluble
on water at ambient temperature to the extent of at least
0.5 weight percent. These salts include the gluconate,
the isothionate (2-hydroxyethanesulfonate), format,
acetate, glutamate, succinamate, monodiglycollate,
dimethanesulfonate, lactate, dii~obutyrate, glucohep-
donate.
Suitable buffers include, for example, sodium or
potassium citrate, citric acid, boric acid, sodium borate,
it sodium bicarbonate and various mixed phosphate buffers,
including combinations of Nope, Nope and KH2P04.
Generally, buffers may be used in amounts ranging from
about 0.05 to about 2.5%, and more preferably, from about
0.1 to 1.5% by weight.
Complete tablets and powders preferably contain in
addition to the toxicity agents, buffers and preservatives
previously described, various sequestering or chelating
agents to bind metal ions, such a calcium which might
Sirius react with protein and collect on lens surfaces.
Lthylenediaminetetraacetic acid (ETA) and its salts
(disodium) are preferred examples. They are normally
added in amounts sufficient to provide a solution
containing from about 0.01 to about 2.0 weight percent.
Although the microbial enzyme cleaning preparations
described herein can be readily prepared with many of the
abuve-identified additives, such that when dissolved in
distilled water for example, will provide a complete,
preserved isotonic-enzymatic cleaning solution, as a
further preferred embodiment these tablets, powders, etc.,
I
1 1
may be prepared free of such additives, including toxicity
agents, buffers, etc. That is, the various water soluble
tablets, granules and powders may be formulated with
suitable inert ingredients, such as carriers, lubricants,
binders or excipients, like polyethylene glycol, sodium
chloride eta" commonly used in the tablet making art.
This embodiment is especially suitable for use in
conjunction with other aqueous lens care products, like
wetting solutions, soaking solutions, cleaning and
conditioning solutions, as well as all purpose type lens
care solutions. Such products contain, for instance,
toxicity agents, pi buffers, cleaning and wetting agents,
sequestering agents, viscosity builders, etc. Thus,
effervescent tablets formulated, for example, with a
mixture of the microbial enzymes and effervescent salts
like citric or tartaric acids and sodium bicarbonate may
be dissolved in any of the readily available OTC solutions
e.g. .., isotonic-preserved saline solution containing a
chelating agent, such as disodium ETA and a surfactant.
Microbial enzyme cleaning activity may be
supplemented with a surfactant type cleaner which may be
used before or after enzymatic cleaning to remove any
residual lipid deposits. In those instances where there
has been a heavy build-up of denatured tear film and
debris on lenses the lipolytic activity of the enzyme may
be supplemented by use of a surfactant-type lens cleaner
When surfactants are used, neutral or non-ionic types are
preferred for their cleaning and conditioning properties
which are usually present in amounts up to 15 weight
percent. Examples of suitable surfactants include, but
are not limited to polyethylene glycol esters of fatty
acids, e.g. coconut, polysorbate, polyoxyethylene, or
polyoxypropylene ethers of higher alikeness (~12-C18).
Examples of preferred surfactants include polysorbate 20
(available under the trademark Tweet 20), polyoxyethylene
~L23~65
(23) laurel ether (Brim 35), polyoxyethylene (40)
Stewart (My; I polyoxyethylene (25), propylene
jackal Stewart (Atlas 2612).
One non-ionic surfactant in particular consisting of
a poly(oxypropylene)-poly(oxyethylene) adduce of ethylene
Damon having a molecular weight from about 7500 to about
27,000 wherein at least 40 weight percent of said adduce
is poly(oxyethylene) has been found to be particularly
useful in cleaning and conditioning both soft and hard
lo contact lenses in amounts from about 0.01 to about 15
percent. Such surfactants are available from BASS-
Wyandotte under the registered trademark --Tetronic.
The microbial protease-amylase and optional Lopez
contact lens cleaners provide several benefits, including
substantially odor-free, non-allergenic, require no
additional activator or stabilizer and are completely
water soluble. In addition, the microbial protozoa-
aimless enzyme cleaners may be conveniently used in
conjunction with contact lens heat disinfection units,
such as those available from Bausch Lomb under the
Austrian trademark which has, for example, a one hour
cleaning cycle where lenses in solution are heated up to
about 80C and then allowed to cool. Thus, high
temperature cleaning and disinfection may be carried out
with the enzyme cleaners of the present invention in one
hour or less without the usual 2 to 12 hour presoaking
and final disinfection. The shorter cleaning cycles are
especially desirable for use in conjunction with extended
wear lenses which can be cleaned with the microbial
protease/amylase product in 30 minutes at a peak
temperature e.g. ... 70C, thereby reducing the
possibility of physical damage, such as discoloration to
the lenses. Details of this one-step cleaning method are
described in cop ending Canadian application
SUN. 465,505, filed on
:-3
~3~06
.
even date herewith.
The following specific examples demonstrate the
composition and methods of the instant invention. It is
to be understood that these examples are for illustrative
purposes only and do not purport to be wholly definitive
as to conditions and scope.
EXAMPLE
In order to study the effectiveness of bacterial
protozoa in removing pretenses film deposits and
debris from contact lenses compressed, water-soluble heat
unit tablets are first prepared with each tablet
containing about 18 my of PROTOZOA A I enzyme
commercially available under the Enzeco trademark from
Enzyme Development Corporation, Copyright, slew Jersey. The
enzyme it derived from B. licheniformis and contains
principally pretty and -aimless activity. The protozoa
activity is approximately 53 cozen un~ts/mg. The enzyme
is stable at a pi of between 5.0 and 10Ø
The enzyme powder it first granulated with a
sufficient amount of a pharmaceutical grade polyethylene
glycol (4000) or other suitable binder and lubricant. The
granulated fines are then formed into compressed tablets
with each tablet weighing approximately 30 my.
EXPEL II
A clear artificial tear solution is prepared
consisting of 0.2 grams of lysozym~/100 ml of electrolyte.
The electrolyte is a stock solution prepared from sodium
bicarbonate 2.2 gel, sodium chloride 7 gel, calcium
chloride 0.0005 gel and potassium chloride 1.5 gel.
Six (6) polymacon soft contact lenses commercially
3 available from Bausch & Lomb under the registered
trademark Softens are microscopically inspected before
coating with the lyceum solution. The lenses are then
'I'
:1.23~(~69
soaked in the lysozyme solution for 30 to 60 minutes at
room temperature. The lenses are then placed individually
into the wells of Lensgard carrying cases and placed
into Bausch & Lomb Austrian heat units in order to
denature the lysozyme protein. The coated lenses are then
placed in other Lensgard carrying cases and covered with
sorbic acid preserved sterile isotonic saline solution
containing Tetronic 1107 surfactant. A single tablet
prepared in Example I is dispensed into each well of the
lo carrying case and the caps for the cases tightly affixed.
Each case is subjected to a heat cycle in a Austrian Lotte
unit having a one hour heating cycle with a maximum
temperature of 80C followed by a cooling off cycle. At
the conclusion of the heating cycle the lenses are removed
from the cases rubbed and rinsed with sorbic acid
preserved sterile isotonic solution containing Tetronic
1107 surfactant. Each of the lenses are then
microscopically inspected. The denatured protein on all
the test lenses is completely removed. No defects or
apparent discolorations are observed in each of the six
lenses.
EXAMPLE III
In order to evaluate the compatibility of the enzyme
cleaning tablets on soft contact lenses a first experiment
is conducted with the enzyme cleaner only. second study
is performed to evaluate the effects of the combination of
the enzyme, preserved lens cleaner and heat on soft
contact lenses.
Six (6) polymacon Softens contact lenses are
3 microscopically inspected for possible defects and
discoloration and are then placed in the wells of three
Lensgard lens carrying cases. Each of the lenses is then
covered with a sorbic acid preserved isotonic saline
~.Z3~1369
60lutlon containing Tetronic 1107 surfactant. Thirty (30~
milligrams of polyethylene glycol us then added to the
well of the first case; a water soluble enzyme tablet from
Example I it placed in each of the wells of the second
case and nothing further it added to the third carrying
case. The caps for the wells are placed on each of the
cases which are then subjected to a single one hour
heating cycle in an automatic Austrian heat unit.
The above procedure is repeated for five times using
loathe same lenses while replenishing the preserved saline
solution, polyethylene glycol and enzyme at the beginning
of each of the cycles. At the conclusion of each of the
cycles the lenses are microscopically inspected. rho
defects or discolorations are observed on any of the six
lionizes and the lenses remained unchanged for the duration
of the study.
EMPLOY IV
An oscular irritation study is performed using
fluoresce in dye retention on corneas of rabbit eyes fitted
wow contact lenses treated in cleaning solutions prepared
with the Enzeco A heat unit enzyme tablets of Example I.
The yes of three rabbits are fitted with Softens
brand polymacon contact lenses, three of which are
cleaned by heating in an Austrian heat unit containing the
enzyme tablets from Example I dissolved in a sorbic acid
preserved isotonic saline solution commercially available
from Bausch & Lomb under the trademark Sensitive Eyes.
The control eye is fitted with a lens heated with a
Sensitive Eyes solution only. All eyes are examined
microscopical each day before insertion and after
removal of the lenses which are worn on an average of six
hours per day for five days. Fluoresce in staining is
performed in conjunction with U/V light prior to
initiation of the study, repeated after three days of
:~3~L069
16
wear and again at the completion of the study. Any
oscular irritation is detected by dye absorption using
slit lamp microscopy.
All eyes exhibit minimal conjunctival redness
probably due to lens wear and manipulation. No positive
fluoresce in staining is observed. Jo positive reactions
are observed microscopically throughout the study.
EXAMPLE V
Comparative studies are conducted to evaluate the
cytotoxicity of lens cleaning solutions prepared with the
heat unit tablets of Example I. The studies utilize the
Ajar Overlay Assay technique published in the Journal of
Pharmaceutical Sciences, Volume 54 (1965) pages 1545-1547
by W. L. Guess et at. Four polymacon Softens contact
lenses are soaked in solution prepared by dissolving
enzyme tablets in the wells of Lensgard lens cases having
sorbic acid preserved isotonic saline solution containing
Tetronic 1107 surfactant. An additional four lenses are
placed in cases containing only the preserved saline-
Tetronic solution which serve as controls. The lenses reheated for one cycle in Austrian heat units and rinsed in
the preserved saline-Tetronic solution, then heat treated
for an additional cycle and rinsed again before being
plated onto L-929 mouse fibroblast cells to observe any
Jo lying of the cells.
~3~()6~9
17
TABLE
Width of
DecolQrlzed Zone
Lens Solution Response Percent of Cells Lucid
Enzyme Non-cytotoxic 0/0
2 Enzyme " 0/0
3 Enzyme " o/o
4 Enzyme " /
Control " 0/0
6 Control " 0/0
7 Control " /
8 Control " 0/0
The absence of a decolonized zone indicates the lack of
lucid cells and absence of a cytotoxic response.
I 9
EXAMPLE VI
Effervescent Enzyme Tablets
Effervescent enzyme cleaning tablets are made by
first preparing an effervescent excipient containing
sodium bicarbonate, citric acid and sodium chloride in a
weigh ratio of 3:1:1. Each of the salts is finely ground
separately in a mortar and then mixed together with the
aid of a mortar and pestle. A small amount of distilled
water e.g. .~. <0.5 ml is added to the mixture and further
lo blended to initiate molecular interaction of the salts.
The mixture is spread evenly on a glass plate and placed
in a vacuum oven for 2 to 3 hours at 60C. The mixture is
then finely ground in a mortar and blended with Enzeco
Protozoa A I enzyme powder in a ratio of excipient to
lo enzyme of 2:1 to provide 100 my of enzyme per tablet.
Tablets are then made by compressing at 2500 prig.
The above tablets are then tested for dissolution
time; solution appearance and effervescence
characteristics. Dissolution in 10 ml of distilled water
requires 37 seconds; a white foam appears initially but
settles shortly thereafter to provide a clear and
colorless solution. Dissolution of the tablet occurred
uniformly.
While the invention has been described in conjunction
with specific examples thereof, this is illustrative only.
~ccordin2ly, many alternatives, modifications and
variations will be apparent to those skilled in the art in
light of the foregoing description, and it is therefore
intended to embrace all such alternatives, modifications
to no variations as to fall within the spirit and broad
scope of the appended claims.
