Note: Descriptions are shown in the official language in which they were submitted.
r CA 02399362 2005-03-14
IMPROVED LOW-COST DENTIFRICE COMPOSITION
FIELD OF THE INVENTION
The present invention relates to an oral care composition. Specifically, the
s present invention relates to a low-cost dentifrice composition.
BACKGROUND OF THE INVENTION
Good oral hygiene may be at least in part achieved by brushing the teeth
with an oral composition such as a dentifrice composition. A dentifrice
~o composition is widely acknowledged as important in contributing to
improving oral
health, especially via a reduction in the incidence of dental cavities and the
build-
up of tartar and dental calculus. Such conditions result from oral plaque, and
may lead to diseases such as periodontis and gingivitis. These diseases remain
a major cause of tooth loss in adults today. In addition, other oral health
afflictions, such as staining of the tooth enamel and oral malodor (bad
breath)
may be reduced by regular tooth brushing with a dentifrice composition.
Although a number of dentifrice compositions have been described and
many types of dentifrices and other oral care compositions are now
commercially
available, there is still the desire and need to develop improved products for
2o promoting oral health. In addition, current dentifrice compositions may
require
expensive ingredients, and or production techniques. Accordingly, such
dentifrice compositions may be too expensive for certain locales, or for
certain
consumer segments. Accordingly, it is desirable to improve the cost-
effectiveness of such products without decreasing their efficacy, so that they
may
2s become increasingly available to consumers of all income levels, and in all
locations.
Previous low cost dentifrice compositions typically contain an abrasive, a
humectant, an aqueous solvent, at least about 15% dihydric and trihydric
alcohols, and a low level of water. However, these dentifrice compositions
3o typically do not contain an anti-cavity agent, because they are typically
expensive. Accordingly, such low-cost dentifrice compositions may not provide
the desired level of anti-caries protection. In addition, high levels of
dihydric and
trihydric alcohols are typically present, because it is commercially important
that
a dentifrice composition possess acceptable physical properties, such as
texture
~
CA 02399362 2005-03-14
and rheology. Consumers typically require an acceptable dentifrice composition
to be, for example, smooth, squeezable, and relatively non-sticky.
Accordingly, the need exists for a dentifrice composition that provides
satisfactory oral health benefits in a cost-effective manner.
SUMMARY OF THE INVENTION
The present invention relates to an improved low-cost dentifrice
composition comprising from about 6% to about 70% of an abrasive polishing
material, from about 0.5% to about 4.5% of a thickener, from about 0.5% to
about 45% of a hexahydric humectant, from about 0.05% to about 2.5% of an
anti-cavity agent, and at least about 30% of water. The composition comprises
less than about 10% dihydric and trihydric alcohols, and has a viscosity of
from
about 8 to about 100 BKU.
It has now been found that the present invention may provide an effective,
~5 stable, and less irritating composition which is both easy to produce and
cost
effective. In addition, such an improved dentifrice composition provides oral
health and/or cavity reduction which is comparable to, or improved over,
current
dentifrice compositions. Furthermore, the flavor release, rheology, and/or
texture
of the improved dentifrice composition may be comparable to, or improved over,
2o current dentifrice compositions.
In accordance with another aspect of the present invention there is
provided a dentifrice composition comprising:
A. from about 10% to about 50% of an abrasive polishing material;
B. from about 0.5% to about 4.5% of a thickener;
25 C. from about 0.5% to about 45% of a hexahydric humectant;
D. from about 0.05% to about 2.5% of an anti-cavity agent; and
E. at least about 30% of water,
wherein the composition is substantially free of dihydric and trihydric
alcohols, and wherein the viscosity of the composition is from about 8 to
3o about 100 BKU.
In accordance with another aspect of the present invention the thickener is
selected from the group consisting of carboxymethyl cellulose, carbomer,
Xanthan gum, and mixtures thereof.
2
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CA 02399362 2005-03-14
In accordance with another aspect of the invention, the dentifrice
composition of the present invention comprises at least 40% water.
In accordance with another aspect of the present invention, in the
dentifrice composition of present invention the hexahydric humectant is
selected
from the group of sorbitol, xylitol, glucose, and mixtures thereof.
In accordance with another aspect of the present invention, in the
dentifrice composition of present invention the viscosity of the composition
is
from about 15 to about 80 BKU.
In accordance with another aspect of the present invention, the dentifrice
composition of present invention further comprises an adjunct compound
selected from the group consisting of a peroxide source, an alkali metal
bicarbonate source, an anti-tartar agent, a surfactant, titanium dioxide, an
antioxidant, a coloring agent, a flavoring system, a sweetening agent, an
herbal
agent, an anti-microbial agent, and mixtures thereof.
In accordance with another aspect of the present invention there is
provided a dentifrice composition comprising:
A. from about 10% to about 50% of a silica abrasive polishing
material;
B. from about 0.5% to about 4.5% of a thickener selected from the
2o group consisting of carboxymethyl cellulose, carbomer, Xanthan
gum, and mixtures thereof;
C. from about 5% to about 30% of a hexahydric humectant selected
from the group consisting of sorbitol, xylitol, glucose, and mixtures
thereof;
2s D. from about 0.1 % to about 1 % of sodium fluoride; and
E. at least about 30% of water,
wherein the composition is substantially free of dihydric and trihydric
alcohols, and wherein the viscosity of the composition is from about 15 to
about 50 BKU.
In accordance with another aspect of the invention, the dentifrice
composition of the present invention comprises at least 40% water.
3
r, r CA 02399362 2005-03-14
In accordance with another aspect of the present invention there is
provided a use of dentifrice compositions according to the present invention
to
clean a dental surface of a human or an animal.
These and other features, aspects, advantages, and variations of the
present invention, and the embodiments described herein, will become evident
to
those skilled in the art from a reading of the present disclosure with the
appended claims, and are covered within the scope of these claims.
~o DETAILED DESCRIPTION OF THE INVENTION
All percentages, ratios and proportions herein are by weight of the final
dentifrice composition, unless otherwise specified. All temperatures are in
degrees Celsius (°C) unless otherwise specified. Citation of any
reference is not
an admission regarding any determination as to its availability as prior art
to the
~s claimed invention.
Herein, "alkyl" means a hydrocarbyl moiety which is straight or branched,
saturated or unsaturated. Unless otherwise specified, alkyl moieties are
preferably saturated or unsaturated with double bonds, preferably with one or
two
double bonds. Included in the term "alkyl" is the alkyl portion of acyl
groups.
2o Herein, "comprising" means that other steps and other components which
do not affect the end result may be added. This term encompasses the terms
"consisting of and "consisting essentially of."
Herein, "effective amount" means an amount of a compound or
composition sufficient to significantly induce a positive benefit, preferably
an oral
2s health benefit, but low enough to avoid serious side effects, i.e., to
provide a
reasonable benefit to risk ratio, within the sound judgment of a skilled
artisan.
Herein, "dentifrice composition" means a composition whose physical form
is a paste or gel composition unless otherwise specified. The dentifrice
composition may be in any desired aesthetic form, such as deep striped,
surface
3o striped, multi-layered, having the gel surrounding the paste, or any
combination
thereof. Alternatively, the dentifrice composition may be a dual-phase system
comprising two or more dentifrice compositions contained in a physically
separated compartment of a dispenser and dispensed side-by-side.
Herein, "dihydric alcohol" indicates a molecule which possess two hydroxy
35 groups, and includes common humectants such as polyethylene glycol,
4
~
~ CA 02399362 2005-03-14
propylene glycol, etc. Herein, "trihydric alcohol" indicates a molecule which
possess three hydroxy groups, and includes common humectants such as
glycerine. Dihydric alcohols and trihydric alcohols are collectively referred
to
herein, as "dihydric and trihydric alcohols".
Herein "dispenser" means any pump, tube, or container suitable for
dispensing the dentifrice composition.
Herein, "substantially free" means that no such compound is purposely
added as an ingredient to the dentifrice composition. However, this term does
not preclude the possibility that a small amount of such a compound may be
present as an impurity, or at a level which does not significantly affect the
overall
performance, cost, and/or stability of the dentifrice composition.
All ingredients such as actives and other ingredients useful herein may be
categorized or described by their cosmetic and/or therapeutic benefit or their
postulated mode of action. However, it is to be understood that the actives
and
~5 other ingredients useful herein can, in some instance, provide more than
one
cosmetic and/or therapeutic benefit or operate via more than one mode of
action.
Therefore, classifications herein are made for the sake of convenience and are
not intended to limit an ingredient to the particular stated application or
applications listed.
Abrasive Polishing Material
The abrasive polishing material useful herein may be selected from any
material which does not excessively abrade dentine. The abrasive polishing
material preferably has a calcium content of less than about 23%. Typical
abrasive polishing materials include silicas including gels and precipitates;
aluminas; phosphates including orthophosphates, polymetaphosphates, and
pyrophosphates; and mixtures thereof. Specific preferred examples of the
abrasive polishing material useful herein include silicas (further described
below),
dicalcium orthophosphate dehydrate, calcium pyrophosphate, tricalcium
3o phosphate, calcium polymetaphosphate, insoluble sodium polymetaphosphate,
hydrated alumina, beta calcium pyrophosphate, calcium carbonate, resinous
abrasive materials such as particulate condensation products of urea and
formaldehyde, dicalcium phosphate, alumina trihydrate, insoluble sodium
metaphosphate, and others such as disclosed by Cooley, et al., in U.S. Patent
3,070,510, issued Dec. 25, 1962. Mixtures of abrasives may also be used.
5
. CA 02399362 2005-03-14
While calcium carbonate may be used herein, it is not preferred as it may be
incompatible with the anti-cavity agent, as described below; therefore, in a
preferred embodiment, the dentifrice composition is substantially free of
calcium
carbonate.
Silica dental abrasives of various types are also highly preferred because
of their unique benefits of exceptional dental cleaning and polishing
performance
without unduly abrading tooth enamel or dentine. The silica abrasive polishing
materials herein, as well as other abrasive polishing materials, generally
have an
average particle size ranging between about 0.1 to about 30 microns,
preferably
from about 5 to about 15 microns, and have good fluoride compatibility (i.e.
to
provide soluble fluoride ions). The abrasive polishing material may be
precipitated silica or silica gels such as the silica xerogels described in
Pader, et
al., U.S. Patent 3,538,230, issued Mar. 2, 1970, and DiGiulio, U.S. Patent
3,862,307, issued Jan. 21, 1975. Preferred are the silica xerogels marketed
~5 under the trade name "Syloid" by the W. R. Grace & Company, Davison
Chemical Division. Also preferred are the precipitated silica materials such
as
those marketed by the J. M. Huber Corporation under the trade name, "Zeodent",
particularly the silica carrying the designation "Zeodent 119T""". The types
of
silica dental abrasive polishing materials useful in the dentifrices of the
present
2o invention are described in more detail in Wason, U.S. Patent 4,340,583,
issued
July 29, 1982. The dentifrice composition comprises an abrasive polishing
material at a level of from about 6% to about 70%, preferably from about 10%
to
about 50%, and more preferably from about 15% to about 30%, by weight of the
dentifrice composition.
Thickener
The thickener useful herein acts as a binder to provide a desirable
consistency. The thickeners useful in the present dentifrice may be selected
from an inorganic gel-forming thickener, a modified cellulose thickener, a
natural
3o vegetable gum thickener, a bacterial gum thickener, a synthetic organic
polymer
thickener, a miscellaneous natural thickener, and a mixture thereof. Preferred
inorganic gel-forming thickeners include a silica precipitate, a silica
aerogel, a
pyrogenic silica, a colloidal magnesium aluminum silicate, and a mixture
thereof.
Preferred modified cellulose thickeners include carboxymethyl cellulose,
hydroxyethyl cellulose, hydroxymethyl carboxyethyl cellulose, hydroxypropyl
6
' CA 02399362 2005-03-14
cellulose, hydroxymethyl carboxypropyl cellulose, methyl cellulose, ethyl
cellulose, and a mixture thereof. Such thickeners are available from, for
example, Aqualon Co., Hopewell, VA, USA; Jiangmen Fenghua Fine Chemical
Industry Co., Ltd., Jiangmen City, China; and Zhangjiagang Xinguang Chemical
Factory, Zhangjiagang City, China. Preferred natural vegetable gum thickeners
include Irish Moss (carrageenan), gum tragacanth, gum arabic, gum ghatti, gum
acacia, locust bean gum, sodium alginate, and a mixture thereof. A preferred
bacterial gum thickener is Xanthan gum. Preferred synthetic organic polymer
thickeners include a polyacrylate, a polyvinyl pyrrolidone, and a mixture
thereof,
more preferably a cross-linked homopolymer of acrylic acid, such as carbomer.
Highly preferred carbomers include those of the CarbopolT"" series, especially
Carbopol 956T"~, available from BF Goodrich Co., Calvert City, Kentucky, USA.
Preferred miscellaneous natural thickeners include agar-agar, pectin, gelatin,
and
a mixture thereof. From a performance, economy, safety, and cost standpoint,
an even more preferred thickener is a carboxymethyl cellulose, a carbomer, and
a mixture thereof.
The thickener is present at a level of from about 0.5% to about 4.5%,
preferably from about 0.5% to about 2.0%, and more preferably from about 0.8%
to about 1.5%, by weight of the dentifrice composition.
Hexahydric Humectant
The present dentifrice composition contains a hexahydric humectant
therein, which serves to keep toothpaste compositions from hardening upon
exposure to air, and typically also impart a desirable sweetness of flavor to
the
2s dentifrice composition. The hexahydric humectant useful herein has six
hydroxyl
groups, and is typically, although not necessarily, a sugar, or derived from a
sugar. The hexahydric humectant may have a linear, branched, or cyclic
backbone; and preferably the hexahydric humectant has a cyclic backbone of
about 6 carbon atoms. The hexahydric humectant may also have one or more
so additional functional groups, such as carboxylic acid moieties, amine
moieties,
amido moieties, ester moieties, and mixtures thereof. More preferably, the
hexahydric humectant is selected from the group consisting of sorbitol,
xylitol,
glucose, and a mixture thereof, and even more preferably, sorbitol. Such
sugars
may further reduce the formulation cost, by reducing or eliminating the need
for
3s an optional sweetener.
' CA 02399362 2005-03-14
Without intending to be limited by theory, it is believed that these
hexahydric humectants, and especially sorbitol, xylitol, glucose, and mixtures
thereof, interact with the thickeners described herein to provide superior
water-
binding abilities due to the accessibility and positioning of their multiple
hydroxyl
s groups. It is further believed that such benefits are not present when, for
example, the level of hexahydric humectant, alone, is increased. This
synergistic
effect in turn may reduce the need for more expensive thickeners and dihydric
and trihydric alcohols, and may further reduce formulation costs while
maintaining an acceptable rheology and texture for the dentifrice composition.
Such hexahydric humectants are also typically easily available, cost
effective,
safe in almost all instances, and are surprisingly stable when included in the
present dentifrice composition.
In addition, it is believed that the high hydrophilicity of such hexahydric
humectants directly improves the flavor retention and flavor release of oil-
based
~5 flavoring systems, and allows a lower level of flavoring to be used. As
flavoring
systems are typically highly distilled, and expensive mixtures, the present
dentifrice composition may have significantly reduced formulation costs.
Because oil-based flavoring systems are relatively insoluble in such a
hydrophilic
compound, more flavor is directly perceivable by a dentifrice composition
user.
2o In contrast, oil-based flavoring systems may be partially or completely
soluble in
dihydric and/or trihydric alcohols, such as glycerin and polyethylene glycol,
which
are common in dentifrice compositions; this in turn reduces the flavoring
system's ability to be perceived by a dentifrice composition user, and may
increase formulation costs by requiring that a greater level of flavoring
system be
2s included.
Without intending to be limited by theory, it is believed that the
combination of the hexahydric humectant and the thickener described herein
synergistically interact to provide acceptable rheology, aesthetics,
stability, and
equal or better performance, without the need for the traditionally high
levels
30 (e.g., 15%, or more) of dihydric and trihydric alcohols. As noted above,
such
dihydric and trihydric alcohols are typically expensive, and therefore the
reduction, or removal of such compounds may significantly reduce the
formulation costs of the dentifrice composition. Accordingly, the dentifrice
composition of the present invention typically comprises less than about 10%,
3s preferably between 0% and about 5% dihydric and trihydric alcohols. More
s
~ ' CA 02399362 2005-03-14
preferably, the dentifrice composition of the present invention is
substantially free
of dihydric and trihydric alcohols.
The hexahydric humectant is typically present at a level of about 0.5% to
about 45%, preferably from about 5% to about 40%, and more preferably from
s about 10% to about 35%, by weight of the dentifrice composition.
Anti-Cavity Agent
The decrease in formulation costs due to the reduction or elimination of
dihydric and trihydric alcohols allows a formulator greater freedom to
include,
~o and/or increase the level of an anti-cavity agent in the dentifrice
composition,
without having to raise the selling price. In certain countries and locales,
this
may increase the availability of good, effective oral health care to a
significant
fraction of the general populace. The anti-cavity agent typically contains a
fluoride ion, preferably a water-soluble fluoride ion. Fluoride ion sources
are well
15 known for use in oral care compositions as anti-caries agents. Fluoride
ions are
contained in a number of oral care compositions for this purpose, particularly
in
dentifrice compositions such as toothpastes. Patents disclosing such
dentifrice
compositions include U.S. Pat. No. 3,538,230, Nov. 3, 1970 to Pader, et al.;
U.S.
Pat. No. 3,689,637, Sept. 5, 1972 to Pader; U.S. Pat. No. 3,711,604, Jan 16,
20 1973 to Colodney, et al.; U.S. Pat. No. 3,911,104, Oct. 7, 1975 to
Harrison; U.S.
Pat. No. 3,935,306, Jan. 27, 1976 to Roberts, et al.; and U.S. Pat. No.
4,040,858,
Aug. 9, 1977 to Wason.
Application of fluoride ions to dental enamel serves to protect teeth
against decay. A wide variety of fluoride ion-yielding materials may be
employed
2s as sources of soluble fluoride in the instant compositions. Examples of
suitable
fluoride ion-yielding materials are found in Briner, et al.; U.S. Pat. No.
3,535,421;
issued Oct. 20, 1970 and Widder, et al.; U.S. Pat. No. 3,678,154; issued July
18,
1972. Preferred fluoride ion sources for use herein include sodium fluoride,
potassium fluoride, ammonium fluoride, sodium monofluorophosphate, stannous
so fluoride, and a mixture thereof. Sodium fluoride is particularly preferred,
and is
available from, for example, Jinan Chemical Sub-factory, Jinan City, Shandong
province, China. Preferably the dentifrice composition provides from about 50
ppm to 10,000 ppm, more preferably from about 100 to 3000 ppm, of fluoride
ions in the compositions that contact dental surfaces when used with the
delivery
35 system of the present invention. Such fluoride ion measurements are
typically
9
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CA 02399362 2005-03-14
determined from a 3:1 slurry of water and dentifrice composition. Generally,
the
anti-cavity agent, preferably the fluoride ion anti-cavity agent, will be
present at a
level of from about 0.05% to about 2.5%, preferably from about 0.1 % to about
1 %, and more preferably from about 0.1 % to about 0.5%, by weight of the
composition.
However, when using fluoride ions as the anti-cavity agent, care should be
taken to reduce interactions with incompatible materials such as calcium
carbonate, which may be present as an abrasive polishing material.
Accordingly,
if a fluoride ion is present, and especially if sodium fluoride is present,
then it is
1o highly preferred that the dentifrice composition be substantially free of
calcium
carbonate. While fluoride ion-containing anti-cavity agents are preferred, non-
fluoride anti-cavity agents known in the art, such as monosodium phosphate,
monohydrate, are also useful herein, either alone, or in combination with a
fluoride ion-containing anti-cavity agent.
Water
The dentifrice composition further contains at least 30% by weight of the
dentifrice composition. As described and measured herein, "water" includes
water from solutions (i.e., a humectant solution, a sweetener solution, a
2o surfactant solution, etc.), but not bound water (i.e., from hydrates at
room
temperature). Prior to addition to the dentifrice composition, the water
useful
herein is typically purified, or distilled to remove impurities.
Adjunct Compound
The dentifrice composition may further contain one or more adjunct
compounds known in the art, preferably an adjunct compound selected from the
group consisting of a dihydric or trihydric humectant, a buffering agent, a
peroxide source, an alkali metal bicarbonate source, an anti-tartar agent, a
surfactant, titanium oxide, an antioxidant, a coloring agent, a flavoring
system, a
3o sweetening agent, an herbal agent, an anti-microbial agent, and a mixture
thereof.
The present invention may comprise up to 10% of a dihydric or trihydric
humectant, such as are traditionally used in dentifrice compositions. However,
in
a preferred embodiment, the dentifrice composition comprises between 0% and
about 5% dihydric and trihydric alcohols. More preferably, the dentifrice
" CA 02399362 2005-03-14
composition of the present invention is substantially free of dihydric and
trihydric
alcohols. Suitable humectants for use in the invention include glycerin,
polyethylene glycol, propylene glycol, other edible polyhydric alcohols, and a
mixture thereof, and preferably glycerin, polyethylene glycol, and a mixture
s thereof.
The present composition typically contains a buffering agent. If the
dentifrice composition is a dual phase system, a buffering agent will be
present in
both dentifrice compositions. Buffering agents, as used herein, refer to
agents
that may be used to adjust the pH of the compositions to a range of about pH 4
1o to about pH 10, with pH of about 4 to about 8 being preferred, and pH of
about
5.5 to about 8 being more preferred. These agents include alkali metal
hydroxides, carbonates, sesquicarbonates, borates, silicates, phosphates,
imidazole, and mixtures thereof. Specific buffering agents include monosodium
phosphate, trisodium phosphate, sodium hydroxide, potassium hydroxide, alkali
15 metal carbonate salts, sodium carbonate, imidazole, pyrophosphate salts,
citric
acid, and sodium citrate. Buffering agents are used at a level of from about
0.01 % to about 30%, preferably from about 0.1 % to about 10%, and more
preferably from about 0.3% to about 7%, by weight of the present composition.
Preferred buffering agents are monosodium phosphate, trisodium phosphate,
2o pyrophosphate salts, citric acid, sodium citrate, and mixtures thereof. It
has
surprisingly been found that the dentifrice composition of the present
invention
does not require as high a level of buffering salts, as traditional dentifrice
compositions. Without intending to be limited by theory, it is believed that
this
may result in reduced irritation to gums, and the oral cavity of the user.
25 Pyrophosphate salts may be present as buffering agents. The
pyrophosphate salts useful in the present compositions include the dialkali
metal
pyrophosphate salts, tetra alkali metal pyrophosphate salts, and mixtures
thereof.
Sodium acid pyrophosphate, disodium dihydrogen pyrophosphate (Na2H2P20~),
tetrasodium pyrophosphate (Na4P207), and tetrapotassium pyrophosphate
30 (K4P207) in their unhydrated as well as hydrated forms are the preferred
species. In compositions of the present invention, the pyrophosphate salt may
be present in one of three ways: predominately dissolved, predominately
undissolved, or a mixture of dissolved and undissolved pyrophosphate.
Compositions comprising predominately dissolved pyrophosphate refer to
3s compositions where at least one pyrophosphate ion source is present. Free
11
' CA 02399362 2005-03-14
pyrophosphate ions may be present in a variety of protonated states depending
on a the pH of the composition.
Compositions comprising predominately undissolved pyrophosphate refer
to compositions containing no more than about 20% of the total pyrophosphate
s salt dissolved in the composition, preferably less than about 10% of the
total
pyrophosphate dissolved in the composition. Tetrasodium pyrophosphate salt
and tetrapotassium pyrophosphate salt are the preferred pyrophosphate salts in
these compositions, with tetrasodium pyrophosphate salt being the more
preferred. Tetrasodium pyrophosphate may be the anhydrous salt form or the
~o decahydrate form, or any other species stable in solid form in the
dentifrice
compositions. The salt is in its solid particle form, which may be its
crystalline
and/or amorphous state, with the particle size of the salt preferably being
small
enough to be aesthetically acceptable and readily soluble during use. The
amount of pyrophosphate salt useful in making these compositions is any tartar
~s control effective amount. Some or all of the tetrasodium pyrophosphate
maybe
undissolved in the product and present as tetrasodium pyrophosphate particles.
Pyrophosphate ions in different protonated states (e.g., HP207-3) may also
exist
depending upon the pH of the composition and if part of the tetrasodium
pyrophosphate is dissolved.
2o Compositions may also comprise a mixture of dissolved and undissolved
pyrophosphate salts. Any of the above mentioned pyrophosphate salts may be
used. The pyrophosphate salts are described in more detail in Kirk & Othmer,
Encyclopedia of Chemical Technology, Third Edition, Volume 17, Wiley-
Interscience Publishers (1982).
2s The present invention may include a peroxide source for whitening effect.
The peroxide source is selected from the group consisting of hydrogen
peroxide,
calcium peroxide, urea peroxide, and mixtures thereof. The preferred peroxide
source is urea peroxide. The following amounts represent the amount of
peroxide raw material, although the peroxide source may contain ingredients
30 other than the peroxide raw material. The present composition may contain
from
about 0.01 % to about 10%, preferably from about 0.1 % to about 5%, more
preferably from about 0.2% to about 3%, and even more preferably from about
0.3% to about 0.8% of a peroxide source, by weight of the composition.
The present invention may also include an alkali metal bicarbonate salt.
3s Alkali metal bicarbonate salts are soluble in water and unless stabilized,
tend to
12
' CA 02399362 2005-03-14
release carbon dioxide in an aqueous system. Sodium bicarbonate, also known
as baking soda, is the preferred alkali metal bicarbonate salt. The alkali
metal
bicarbonate salt also may function as a buffering agent. The present
composition may contain from about 0.5% to about 50%, preferably from about
0.5% to about 30%, more preferably from about 2% to about 20%, and most
preferably from about 5% to about 18% of an alkali metal bicarbonate salt, by
weight of the oral composition.
Anti-tartar agents known for use in dental care products include
phosphates. Phosphates include pyrophosphates, polyphosphates,
1o polyphosphonates and mixtures thereof. Pyrophosphates are among the best
known for use in dental care products. Pyrophosphate and polyphosphate ions
are delivered to the teeth derive from pyrophosphate polyphosphate salts. The
pyrophosphate salts useful in the present compositions include the dialkali
metal
pyrophosphate salts, tetra-alkali metal pyrophosphate salts, and mixtures
thereof. Sodium acid pyrophosphate, disodium dihydrogen pyrophosphate
(Na2H2P2O7), tetrasodium pyrophosphate (Na4P207), and tetrapotassium
pyrophosphate (K4P207) in their unhydrated as well as hydrated forms are the
preferred species. While any of the above mentioned pyrophosphate salts may
be used, tetrasodium pyrophosphate salt is preferred. Sodium polyphosphate
2o and triethanolamine polyphosphates, for example, are preferred.
The pyrophosphate salts are described in more detail in Kirk & Othmer,
Encyclopedia of Chemical Technology, Third Edition, Volume 17, Wiley-
Interscience Publishers (1982). Additional anti-calculus agents include
pyrophosphates or polyphosphates disclosed in U.S. Patent No. 4,590,066
issued to Parran & Sakkab on May 20, 1986; polyacrylates and other
polycarboxylates such as those disclosed in U.S. Patent No. 3,429,963 issued
to
Shedlovsky on February 25, 1969 and U.S. Patent No. 4,304,766 issued to
Chang on December 8, 1981; and U.S. Patent No. 4,661,341 issued to Benedict
& Sunberg on April 28, 1987; polyepoxysuccinates such as those disclosed in
3o U.S. Patent No. 4,846,650 issued to Benedict, Bush & Sunberg on July 11,
1989;
ethylenediaminetetraacetic acid as disclosed in British Patent No. 490,384
dated
February 15, 1937; nitrilotriacetic acid and related compounds as disclosed in
U.S. Patent No. 3,678,154 issued to Widder & Briner on July 18, 1972;
polyphosphonates as disclosed in U.S. Patent No. 3,737,533 issued to Francis
on June 5, 1973, U.S. Patent No. 3,988,443 issued to Ploger, Schmidt-Dunker &
13
CA 02399362 2005-03-14
Gloxhuber on October 26, 1976 and U.S. Patent No. 4,877,603 issued to
Degenhardt & Kozikowski on October 31, 1989. Anticalculus phosphates include
potassium and sodium pyrophosphates; sodium tripolyphosphate;
diphosphonates, such as ethane-1-hydroxy-1,1-diphosphonate, 1-
s azacycloheptane-1,1-diphosphonate, and linear alkyl diphosphonates; linear
carboxylic acids; and sodium zinc citrate.
Anti-tartar agents that may be used in place of, or in combination with the
pyrophosphate salt include such known materials as synthetic anionic polymers
including polyacrylates and copolymers of malefic anhydride or acid and methyl
~o vinyl ether (e.g., GantrezT""), as described, for example, in U.S. Patent
4,627,977, to Gaffar, et al.; as well as, e.g., polyamino propane sulfonic
acid
(AMPS), zinc citrate trihydrate, polyphosphates (e.g., tripolyphosphate;
hexametaphosphate), diphosphonates (e.g., EHDP; AHP), polypeptides (such as
polyaspartic and polyglutamic acids), and mixtures thereof.
15 The present compositions may also comprise a surfactant, also commonly
referred to as a sudsing agent. Suitable surfactants are those which are
reasonably stable and foam throughout a wide pH range. The surfactant may be
anionic, nonionic, amphoteric, zwitterionic, cationic, or mixtures thereof.
Anionic
surfactants useful herein include the water-soluble salts of alkyl sulfates
having
2o from 8 to 20 carbon atoms in the alkyl radical (e.g., sodium alkyl sulfate)
and the
water-soluble salts of sulfonated monoglycerides of fatty acids having from 8
to
20 carbon atoms. Sodium lauryl sulfate and sodium coconut monoglyceride
sulfonates are examples of anionic surfactants of this type. Sodium Lauryl
sulfate is available from, for example, Rhodia Specialty Chemical Wuxi
company,
2s Wuxi City, Jiangsu province, China. Other suitable anionic surtactants are
sarcosinates, such as sodium lauroyl sarcosinate, taurates, sodium lauryl
suifoacetate, sodium lauroyl isethionate, sodium laureth carboxylate, and
sodium
dodecyl benzenesulfonate. Mixtures of anionic surfactants may also be
employed. Many suitable anionic surfactants are disclosed by Agricola, et al.,
3o U.S. Patent 3,959,458, issued May 25, 1976. Nonionic surfactants which may
be
used in the compositions of the present invention may be broadly defined as
compounds produced by the condensation of alkylene oxide groups (hydrophilic
in nature) with an organic hydrophobic compound which may be aliphatic or
alkyl-
aromatic in nature. Examples of suitable nonionic surfactants include
35 poloxamers (sold under trade name Pluronic), polyoxyethylene,
polyoxyethylene
14
"' ~ CA 02399362 2005-03-14
sorbitan esters (sold under trade name Tweens), fatty alcohol ethoxylates,
polyethylene oxide condensates of alkyl phenols, products derived from the
condensation of ethylene oxide with the reaction product of propylene oxide
and
ethylene diamine, ethylene oxide condensates of aliphatic alcohols, long chain
tertiary amine oxides, long chain tertiary phosphine oxides, long chain
dialkyl
sulfoxides, and mixtures of such materials. The amphoteric surfactants useful
in
the present invention may be broadly described as derivatives of aliphatic
secondary and tertiary amines in which the aliphatic radical may be a straight
chain or branched and wherein one of the aliphatic substituents contains from
1o about 8 to about 18 carbon atoms and one contains an anionic water-
solubilizing
group, e.g., carboxylate, sulfonate, sulfate, phosphate, or phosphonate. Other
suitable amphoteric surfactants are betaines, specifically cocamidopropyl
betaine. Mixtures of amphoteric surfactants may also be employed. Many of
these suitable nonionic and amphoteric surfactants are disclosed by Gieske, et
al., U.S. Patent 4,051,234, issued September 27, 1977. The present
composition typically comprises one or more surfactants each at a level of
from
about 0.25% to about 12%, preferably from about 1 % to about 10%, and more
preferably from about 1 % to about 8°l°, by weight of the
composition.
Titanium dioxide may also be added to the dentifrice composition.
2o Titanium dioxide is a white powder which adds opacity to the compositions.
Titanium dioxide generally comprises from about 0.1 % to about 5%, by weight
of
the composition.
An antioxidant is generally recognized as useful in the present
composition, and may be included herein. Antioxidants are disclosed in texts
such as Cadenas and Packer, The Handbook of Antioxidants, ~ 1996 by Marcel
Dekker, Inc. Antioxidants that may be included in the oral care composition or
substance of the present invention include, but are not limited to Vitamin E,
ascorbic acid (vitamin C), uric acid, carotenoids, Vitamin A, flavonoids,
herbal
antioxidants, melatonin, aminoindoles, lipoic acids and mixtures thereof.
3o Vitamins E and C are preferred, with levels of from about 0.01 % to about
0.10%
being desirable, and about 0.01 % to about 0.05% being preferred.
One or more coloring agents may also be added to the present
composition. The coloring agent may be in the form of an aqueous solution,
preferably 1 % coloring agent in a solution of water. Color solutions
generally
s5 comprise from about 0.01 % to about 5%, by weight of the composition.
CA 02399362 2005-03-14
A flavoring system may also be added to the compositions. Suitable
flavoring components include tea mint, oil of wintergreen, oil of peppermint,
oil of
spearmint, clove bud oil, menthol, anethole, methyl salicylate, eucalyptol,
cassia,
1-menthyl acetate, sage, eugenol, parsley oil, oxanone, alpha-irisone,
marjoram,
lemon, orange, propenyl guaethol, cinnamon, vanillin, ethyl vanillin,
heliotropine,
4-cis-heptenal, diacetyl, methyl-para-tert-butyl phenyl acetate, and mixtures
thereof. Non-limiting examples of commercially available flavoring systems
include those sold under the trade names "Smoothmint," "Ultimint," and "Icy
Mint," available from International Flavors and Fragrances, USA & China.
1o Coolants may also be part of the flavoring system. Preferred coolants in
the
present compositions are the paramenthan carboxyamide agents such as N-
ethyl-p-menthan-3-carboxamide (known commercially as "WS-3") and mixtures
thereof. A flavoring system is generally used in the compositions at levels of
from about 0.001 % to about 5%, by weight of the composition.
A sweetening agent may be added to the present composition, such as
saccharin, dextrose, sucrose, lactose, maltose, levulose, aspartame, sodium
cyclamate, D-tryptophan, dihydrochalcones, acesulfame, and mixtures thereof.
Sweetening agents are generally used in toothpastes at levels of from about
0.005% to about 5%, by weight of the composition.
2o An herbal agent, including but not limited to, golden thread extract,
honeysuckle extract, and a mixture thereof, may also be present in the
compositions herein at levels of from about 0.01 % to about 0.05%. Such herbal
agents are believed to provide anti-bacterial efficacy.
While not required, traditional anti-microbial agents may also be present in
2s the dentifrice composition of the present invention. However, as they tend
to be
expensive, and as the present invention shows surprising stability without
them, a
preferred embodiment of the present invention is substantially free of
traditional
anti-microbial agents. A preferred traditional anti-microbial agent is 5-
chloro-2
(2,4-dichlorophenoxy)-phenol, commonly referred to as triclosan, and is
3o described in The Merck Index, 11th ed. (1989), p. 1529 (entry no. 9573), in
U.S.
Patent No. 3,506,720, and in European Patent Application No. 0,251,591 of
Beecham Group, PLC, published January 7, 1988. Other specific antimicrobial
agents include chlorhexidine, triclosan monophosphate, and essential oils
including thymol, geraniol, carvacrol, citral, hinokitiol, eucalyptol, and
mixtures
3s thereof. Triclosan and other agents of this type are disclosed in Parran,
Jr., et
16
CA 02399362 2005-03-14
al., U.S. Patent 5,015,466, issued May 14, 1991, and U.S. Patent 4,894,220,
Jan. 16, 1990 to Nabi, et al. These agents may be present at levels of from
about 0.01 % to about 1.5%, by weight of the composition.
Also included among such other anti-microbial agents are water insoluble
s non-cationic antimicrobial agents such as halogenated diphenyl ethers,
phenolic
compounds including phenol and its homologs, mono and poly-alkyl and
aromatic halophenols, resorcinol and its derivatives, bisphenolic compounds
and
halogenated salicylanilides, benzoic esters, and halogenated carbanilides. The
water soluble anti-microbials include quaternary ammonium salts and bis
1o biquanide salts, among others. Triclosan monophosphate is also a suitable
water soluble antimicrobial agent. The quaternary ammonium agents include
those in which one or two of the substitutes on the quaternary nitrogen has a
carbon chain length (typically alkyl group) from about 8 to about 20,
typically from
about 10 to about 18 carbon atoms while the remaining substitutes (typically
alkyl
1s or benzyl group) have a lower number of carbon atoms, such as from about 1
to
about 7 carbon atoms, typically methyl or ethyl groups. Dodecyl trimethyl
ammonium bromide, tetradecylpyridinium chloride, domiphen bromide, N-
tetradecyl-4-ethyl pyridinium chloride, dodecyl dimethyl (2-phenoxyethyl)
ammonium bromide, benzyl dimethylstearyl ammonium chloride, cetyl pyridinium
2o chloride, quaternized 5-amino-1,3-bis(2-ethyl-hexyl)-5-methyl hexa
hydropyrimidine, benzalkonium chloride, benzethonium chloride and methyl
benzethonium chloride are exemplary of typical quaternary ammonium
antibacterial agents. Other compounds are bis[4-(R-amino)-1-pyridinium]
alkanes as disclosed in U.S. Patent 4,206,215, issued June 3, 1980, to Bailey.
25 Stannous salts such as stannous pyrophosphate and stannous gluconate and
other anti-microbials such as copper bisglycinate, copper glysinate, zinc
citrate,
and zinc lactate may also be included. Also useful are enzymes, including
endoglycosidase, papain, dextranase, mutanase, and mixtures thereof. Such
agents are disclosed in U.S. Patent 2,946,725, Jul. 26, 1960, to Norris, et
al., and
3o in U.S. Patent 4,051,234, September. 27, 1977 to Gieske, et al.
Also suitable for use as anti-microbial agents herein are phthalic acid and
its salts including, but not limited to those disclosed in U.S. Pat.
4,994,262, Feb.
19, 1991, preferably magnesium monopotassium phthalate, chlorhexidine (Merck
Index, no. 2090), alexidine (Merck Index, no. 222; hexetidine (Merck Index,
no.
35 4624); sanguinarine (Merck Index, no. 8320); benzalkonium chloride (Merck
17
CA 02399362 2005-03-14
Index, no. 1066); salicylanilide (Merck Index, no. 8299); domiphen bromide
(Merck Index, no. 3411); cetylpyridinium chloride (CPC) (Merck Index, no.
2024;
tetradecylpyridinium chloride (TPC); N-tetradecyl-4-ethylpyridinium chloride
(TDEPC); octenidine; delmopinol, octapinol, and other piperidino derivatives;
s nicin preparations; zinc/stannous ion agents; antibiotics such as augmentin,
amoxicillin, tetracycline, doxycycline, minocycline, and metronidazole; and
analogs and salts of the above; methyl salicylate; hydrogen peroxide; metal
salts
of chlorite and mixtures thereof.
18
- CA 02399362 2005-03-14
Method of Use
in practicing the present invention, the user need only apply the dentifrice
composition herein, to the tooth surfaces of a human or animal, in the areas
desired, in order to obtain a desired effect, e.g., whitening, breath
freshening,
s caries prevention, pain relief, gum health, tartar control, etc. The
compositions
may also be applied to other oral cavity surfaces, such as the gingival or
mucosal
tissues, although it is believed that the benefits are best achieved when the
dentifrice compositions are applied to the teeth. The dentifrice composition
may
contact the tooth and/or oral cavity surface either directly, or indirectly;
however,
1o it is preferred that the dentifrice composition be directly applied. The
dentifrice
composition may be applied by any means, but is preferably applied with a
brush.
Method of Manufacture
15 The dentifrice composition may be formed by traditional means and
techniques known in the art. For example, the hexahydric humectant, and any
optional dihydric and trihydric alcohols, may be added to purified water, and
homogenized with the anti-cavity agent in a blender, for about 2 minutes. A
sweetening agent, an anti-microbial agent, and other adjunct compounds (other
2o than the flavoring system, surfactant, and titanium oxide) may then be
added,
and the mixture homogenized for an additional 10 minutes. The thickener and
titanium oxide are then added into the mixture, under vacuum of about 0.1-0.2
bar, for about 20 minutes to remove air bubbles. Surfactant, and flavoring are
then added, and homogenized under vacuum for from 15 to 30 minutes to form
25 the final dentifrice composition. The dentifrice composition is then
packaged in
individual dispensers, e.g., toothpaste tubes, for shipment and sale.
The final dentifrice composition typically has a viscosity of from about 8 to
about 100 BKU, preferably from about 15 to about 80 BKU, and more preferably
from about 15 to about 50 BKU. As used herein, "BKU" is the unit of viscosity.
3o The viscometer is BrookfieldT"" viscometer, Model 1/2 RVT (1/2 spring
strength),
with a Brookfield "HelipathT""" stand. The spindle is a conventional "E-
series" T-
shaped spindle. The viscometer is placed on the Helipath stand and leveled via
spirit levels. The E spindle is attached, and the viscometer is set to 2.5 RPM
while it is running. The viscosity is measured after 10 minutes and the
3s temperature is constant, at 25 °C. Commercially acceptable
dentifrice
compositions typically have an acceptable rheology, good texture, pleasing
19
CA 02399362 2005-03-14
aesthetic characteristics, and a specific gravity greater than water,
preferably
from about 1 to 1.5 g/mL, more preferably from about 1.1 to about 1.3 g/mL. A
dentifrice having the above viscosity and specific gravity are usually
acceptable
to consumers.
Examples of the invention are set forth hereinafter by way of illustration
and are not intended to be in any way limiting of the invention.
CA 02399362 2005-03-14
EXAMPLES 1-2
The following dentifrice compositions are prepared according to the
method described above.
Comparative
Com onent Exam 1e Exam 1e Exam 1e
A 1 2
Sodium fluoride, USP 0.25 0.25 0.25
Silica, reci itated Zeodent20 20 20
119
Sorbitol 30.4 21 14
Purified water * 29.4 53.85 60.8
Triclosan, USP 0.05 -- 0.05
Carbo 01956 0.2 0.3 0.3
Sodium carbo meth I cellulose.85 1 1
Sodium saccharin, USP 0.15 0.25 0.25
Trisodium phosphate, 1.3 0.5 0.5
dodecah drate
Sodium alk I sulfate 2.1 1.8 1.8
Flavorin s stem 0.8 0.8 0.8
Titanium dioxide, USP 0.5 0.25 0.25
Rutile
GI cerin 10 -- --
Pol eth lene I col 4 -- --
TOTAL 100 100 100
Brookfield viscosity (BKU)13-37 18 15
(after
minutes
H 6.8-7.4 6.8 6.8
Soluble fluoride level 265-315 268 ppm 268 ppm
(3:1 slurry ppm
of purified water: dentifrice
com osition
Specific gravity (g/mL) 1.32-1.38 1.2 1.2
* includes water from sorbitol solution, surfactant solution, etc.
s Nonlimiting examples of the dentifrice compositions of the invention are
described by Examples 1 and 2, and a Comparative Example A is also provided.
All three formulations provide surprisingly good theology and stability;
however,
the per-unit formulation cost of the Comparative Example A is about 50%
greater
than the formulation costs of Examples 1 and 2. Furthermore, Examples 1 and 2
21
CA 02399362 2005-03-14
possess excellent stability even though they contain more than 50% water.
Furthermore, Examples 1 and B provide improved flavor release (i.e.,
perceptibility of flavor), at the same flavoring system level as Comparative
Example A. Surprisingly, after 1 month, the microbial growth of Example 1 is
s comparable to that of the Comparative Example A, and Example 2, even though
Example 1 lacks Triclosan.
EXAMPLES 3-4
The following dentifrice compositions are prepared according to the
~o method described above.
Com onent Exam 1e 3 Exam to 4
Sodium fluoride, USP 0.243 0.243
Silica, reci itated Zeodent 119 22 21
Sorbitol 30 30
Purified water * 32.657 38.057
Carbo 01956 0.3 0.3
Sodium carbo meth I cellulose 1 1.1
Sodium saccharin, USP 0.25 0.25
Trisodium hos hate, dodecah drate 3 0.5
Monosodium hos hate 2 --
Sodium alk I sulfate 7.5 7.5
Flavorin s stem 0.8 0.8
Titanium dioxide, USP Rutile 0.25 0.25
TOTAL 100 100
Brookfield viscosit BKU after 10 21 18
minutes
6.8 6.8
Soluble fluoride level (3:1 slung 268 ppm 268 ppm
of purified
water: dentifrice com osition
Specific gravity (g/mL) 1.29 1.22
* includes water from sorbitol solution, surfactant solution, etc.
22
