U.S. patent number 3,885,028 [Application Number 05/291,315] was granted by the patent office on 1975-05-20 for fluoride-containing toothpaste.
This patent grant is currently assigned to Alberto-Culver Company. Invention is credited to John A. Cella, William H. Schmitt.
United States Patent |
3,885,028 |
Cella , et al. |
May 20, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Fluoride-containing toothpaste
Abstract
Toothpaste of the type which does not liberate oxygen in the
presence of water, which is free or essentially free of mineral oil
and animal and vegetable triglyceride oils, and having improved
tooth cleaning properties comprising an abrasive agent, in major
proportion based upon the weight of the solid ingredients of the
toothpaste, a small percentage of a fluorine-containing compound,
and at least 20%, by weight, of the total of the liquid ingredients
of said toothpaste, of at least one water-soluble
polyoxyalkyleneglycol having an average molecular weight of at
least 200.
Inventors: |
Cella; John A. (Lake Forest,
IL), Schmitt; William H. (Branford, CT) |
Assignee: |
Alberto-Culver Company (Melrose
Park, IL)
|
Family
ID: |
26707603 |
Appl.
No.: |
05/291,315 |
Filed: |
September 22, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
31789 |
Apr 24, 1970 |
3703578 |
Nov 21, 1972 |
|
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Current U.S.
Class: |
424/52;
424/57 |
Current CPC
Class: |
A61K
8/22 (20130101); A61Q 11/00 (20130101); A61K
8/21 (20130101); A61K 8/86 (20130101) |
Current International
Class: |
A61k 007/16 () |
Field of
Search: |
;424/49-58 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Huff; Richard L.
Attorney, Agent or Firm: Wallenstein, Spangenberg, Hattis
& Strampel
Parent Case Text
This application is a continuation-in-part of application Ser. No.
31,789, filed April 24, 1970, now Pat. No. 3,703,578 dated Nov. 21,
1972.
Claims
What is claimed is:
1. A non-foamable toothpaste containing (a) a major proportion of a
toothpaste abrasive based on the weight of the solids of said
toothpaste, said abrasive consisting essentially of at least one
member selected from the group consisting of precipitated calcium
carbonate, dicalcium phosphate dihydrate, dicalcium phosphate
anhydrous, dibasic calcium phosphate, tribasic calcium phosphate,
calcium pyrophosphate, calcium sulfate, hydrated alumina and
insoluble sodium metaphosphate, (b) from about 0.01% to about 0.4%,
0.4%, by weight of the toothpaste, of a fluorine-containing
compound which is ionizable in water to yield fluoride ions, (c) at
least one paste-forming ingredient, (d) at least 20%, by weight of
the total of the liquid ingredients of said toothpaste, of at least
one water-soluble polyoxyalkyleneglycol having an average molecular
weight of at least 200, the alkylene radicals of said
polyoxyalkyleneglycol containing from 2 to 4 carbon atoms, said
polyoxyalkyleneglycol constituting at least about 15% by weight of
the toothpaste, said toothpaste being essentially free of mineral
oil, vegetable and animal triglyceride oils.
2. A toothpaste according to claim 1, wherein said toothpaste
contains from about 15 to about 45% of a polyoxyalkyleneglycol by
weight of said toothpaste and wherein said polyoxyalkyleneglycol is
a polyoxyethyleneglycol having an average molecular weight between
about 650 and 670.
3. A toothpaste according to claim 1, wherein the
polyoxyalkyleneglycol comprises two different
polyoxyethyleneglycols one of which is a normally solid
polyoxyethyleneglycol having an average molecular weight of about
700 and the other of which is a normally solid
polyoxyethyleneglycol having an average molecular weight of about
4000, the polyoxyethyleneglycol 4000 being present in lesser
proportions than the proportions of the polyoxyethyleneglycol
700.
4. A toothpaste according to claim 1, wherein said
polyoxyalkyleneglycol comprises polyoxyethyleneglycols and wherein
said toothpaste contains from about 35 to about 60% of
polyoxyethyleneglycol, having an average molecular weight of about
700, based on the weight of the total of the liquid ingredients of
the toothpaste, and from about 5 to about 12% of a
polyoxyethyleneglycol, having an average molecular weight of about
4000, based on the weight of said toothpaste.
5. A toothpaste according to claim 1, in which the
fluorine-containing compound is at least one member selected from
the group consisting of sodium fluoride, stannous fluoride,
titanium tetrafluoride and octafluorozirconotin.
6. A toothpaste according to claim 5, in which the toothpaste
abrasive is dicalcium phosphate dihydrate.
7. A toothpaste according to claim 1, which includes an aluminum
soap of a fat-forming fatty acid.
8. A toothpaste according to claim 7 in which the
polyoxyalkyleneglycol is a normally solid polyoxyethyleneglycol
having an average molecular weight of about 700.
9. A toothpaste according to claim 8, which contains aluminum
stearate.
10. A non-foamable toothpaste having an RDA value of not more than
200 and containing (a) a major proportion of a mild toothpaste
abrasive based on the weight of the solids of said toothpaste, said
abrasive consisting essentially of at least one member selected
from the group consisting of precipitated calcium carbonate,
dicalcium phosphate dihydrate, dicalcium phosphate anhydrous,
dibasic calcium phosphate, tribasic calcium phosphate, calcium
pyrophosphate, calcium sulfate, hydrated alumina and insoluble
sodium metaphosphate, (b) from about 0.01% to about 0.4%, by weight
of the toothpaste, of a fluorine-containing compound which is
ionizable in water to yield fluorine ions, (c) at least one
paste-forming ingredient, and (d) at least 20%, by weight of the
total of the liquid ingredients of said toothpaste, of at least one
water-soluble polyoxyalkyleneglycol having an average molecular
weight of at least 200, the alkylene radicals of said
polyoxyalkyleneglycol containing from 2 to 4 carbon atoms, said
polyoxyalkyleneglycol constituting at least about 15% by weight of
the toothpaste, said toothpaste being essentially free of mineral
oil, vegetable and animal triglyceride oils.
11. A toothpaste according to claim 10, wherein said
polyoxyalkyleneglycol is a polyoxyethyleneglycol and wherein said
toothpaste contains from about 15 to about 45% of said
polyoxyethyleneglycol by weight of said toothpaste, said
polyoxyethyleneglycol having an average molecular weight between
about 650 and 750.
12. A toothpaste according to claim 10, wherein the
polyoxyalkyleneglycol comprises two different
polyoxyethyleneglycols one of which is a normally solid
polyoxyethyleneglycol having an average molecular weight of about
700 and the other of which is a normally solid
polyoxyethyleneglycol having an average molecular weight of about
4000, the polyoxyethyleneglycol 4000 being present in lesser
proportions than the proportions of the polyoxyethyleneglycol
700.
13. A toothpaste according to claim 10, which includes an aluminum
soap of a fat-forming fatty acid.
14. A toothpaste according to claim 13, wherein said
polyoxyalkyleneglycol comprises polyoxyethyleneglycols and wherein
said toothpaste contains from about 30 to about 60% of a
polyoxyethyleneglycol, having an average molecular weight of about
700, based on the weight of the total of the liquid ingredients of
the toothpaste, and from about 5 to about 12% of a
polyoxyethyleneglycol, having an average molecular weight of about
4000, based on the weight of said toothpaste.
15. A toothpaste according to claim 10, in which the
fluorine-containing compound is at least one member selected from
the group consisting of sodium fluoride, stannous fluoride,
titanium tetrafluoride and octafluorozirconotin.
16. A toothpaste according to claim 15, in which the toothpaste
abrasive is dicalcium phosphate dihydrate.
17. A toothpaste according to claim 10 in which the
polyoxyalkyleneglycol is a polyoxyethyleneglycol and wherein said
toothpaste contains about 20% to 30% by weight of said
polyoxyethyleneglycol, said polyoxyethyleneglycol having an average
molecular weight of about 700.
18. A toothpaste according to claim 17, which contains aluminum
stearate.
19. A toothpaste according to claim 17, in which the RDA value of
said toothpaste is between about 90 and 150.
20. A toothpaste according to claim 19, in which the
fluorine-containing compound is at least one member selected from
the group consisting of sodium fluoride, stannous fluoride,
titanium tetrafluoride and octafluorozirconotin.
21. A toothpaste according to claim 20, in which the toothpaste
abrasive is dicalcium phosphate dihydrate.
Description
This invention relates to improved toothpastes of the type which
contain fluorine-containing compounds and which, therefore, possess
the well known advantages as to caries inhibiting properties
arising from said fluorine-containing compounds. The toothpastes of
the present invention are, additionally, in their particularly
advantageous embodiments, characterized by substantially enhanced
cleaning properties with low abrasion characteristics. The
toothpastes are based upon special formulations which also make for
a stable system for said fluorine-containing compounds so that they
can maintain their effectiveness over prolonged storage times and a
variety of storage conditions.
Conventional toothpaste formulations comprise a mixture of a number
of solid ingredients with a mixture of a number of liquid
ingredients all of which, together, produce a product of suitable
paste consistency. The solid ingredients of the toothpaste
formulation comprise one or more abrasives, and, in certain cases,
detergents and miscellaneous ingredients such as gums, sweeteners,
thickeners, etc., the abrasive constituting at least the major
proportion, that is, in excess of 50%, by weight, of the total of
the solid ingredients of the toothpaste formulation. The liquid
ingredients of the toothpaste formulation usually comprise water,
humectant, and, commonly, very minor constituents such as flavors
or flavoring oils.
Numerous efforts have been made to provide toothpastes which clean
the teeth rapidly as well as impart an enhanced polish. One of such
approaches lies in the selection of the abrasive ingredient or
ingredients of the toothpaste formulation. The use of relatively
harsher abrasives will sometimes result in a more rapid and more
complete cleaning of the teeth brushed with toothpastes containing
the same than if abrasives with a milder abrading action are used
in the toothpastes. This type of approach to bring about more rapid
and more complete cleaning of the teeth is, generally, not
preferred because of the adverse effects on exposed dentin and oral
health.
Accepted Dental Therapeutics 1969/70, published by the American
Dental Society, discusses the function of an abrasive and states
the "Dentifrices should certainly be free from very harsh
abrasives, such as materials that can scratch enamel." It further
states "there has been a recent tendency to promote dentifrices on
the basis of their ability to whiten or brighten teeth. Such claims
appear to relate almost exclusively to the incorporation in the
dentifrices of harsher abrasive agents such as calcium carbonate,
anhydrous dibasic calcium phosphate, or silica. Highly abrasive
products should not be used regularly by individuals having exposed
cementum or dentin, or possibly, by individuals with restored tooth
surfaces of the softer synthetic materials." It concludes that
"there would appear to be no valid reason for use of a dentifrice
with a greater abrasiveness than is necessary to prevent residual
accumulation on the teeth."
An early report concerning the abrasion properties of dentifrice
cleaning and polishing agents was made in a paper entitled
"Experiments and Observations on the Wasting of Tooth Tissue
Variously Designated as Erosion Abrasion, Chemical Abrasion,
Denudation, Etc., "Dent. Cosmos, 49:1-23; 109-124; 225-247; 1907,
the author concluding commonly used dentifrices at that time were
capable of producing damage to the teeth. Similar results were
obtained by various later investigators.
Studies have also been made on the necessity of an abrasive in a
dentifrice. Manly, R. S.: A Structureless Recurrent Deposit on
Teeth, J. Dent. Res. 22:479-486, 1943, and McCauley et al.,
Clinical Efficacy of Powder and Paste Dentifrices, J. Amer. Dent.
Assoc. 33:993-997, 1946, noted a high incidence of pellicle in
persons using a nonabrasive dentifrice. Phillips and Van Huysen:
Dentifrices and the Tooth Surface, Amer. Perf. 50:33-41, 1948,
reported a high incidence of tooth discoloration from the
collection of material on the tooth surface. Vallotton, C. F: An
Acquired Pigmented Pellicle of the Enamel Surface, J. Dent. Res.
24:161-169, 1945, and Kitchin, P. C., and Robinson, H. B. G.: How
Abrasive Need a Dentifrice Be? J. Dent. Res. 27:501-506, 1948,
reported that the teeth of about two thirds of the persons using a
liquid dentifrice with no abrasive system had a variety of stains.
Kitchin and Robinson in the same paper also found that only 4% of
subjects brushing with water alone failed to form stains within a
two week period. Dudding et al: Patient Reactions to Brushing Teeth
with Water, Dentifrice, or Salt and Soda, J. Periodont 31:386-392,
1960, found that toothbrushing without the use of a dentifrice
resulted in pellicle formation in 93% of the subjects after a five
week study compared to only 9% when a dentifrice was used. Kitchin
and Robinson, in their evaluation of the ability of commercial
dentifrices to prevent pellicle formation, suggested that the
cleaning ability was related to abrasiveness to dentin.
It is apparent from the foregoing studies on abrasion and cleaning
that the usual method of increasing tooth cleaning generally
results in a dentifrice having a high level of abrasion for
dentin.
The abrasiveness of a dentrifrice has most recently been determined
by the so-called RDA method of Grabenstetter, et al., in their
paper The Measurement of the Abrasion of Human Teeth by Dentifrice
Abrasion: A Test Utilizing Radioactive Teeth, J. Dent. Res.
37:1060-1068, 1958. This method utilizes freshly extracted human
teeth, which are irradiated, producing the radio nuclide, p.sup.32,
a high energy Beta emitter with a half life of 14.3 days. This
irradiated tooth is brushed with a mechanical toothbrush, across
the dentin. Using a mica end-window Geiger-Muller counter for which
the background estimated activity of a dried P.sup.32 source is
10.sup.-.sup.4 microcuries, it is possible to determine
10.sup.-.sup.7 g of worn dentin in the abrasive slurry.
A recent paper by Stookey and Muhler, Laboratory Studies Concerning
the Enamel and Dentin Abrasion Properties of Common Dentifrice
Polishing Agents, J. Dent. Res. 47:524-532, 1968, utilized the RDA
method to evaluate thirty-six commercial paste dentifrices. They
found RDA values of 82 to 1019. There were eight products that
could be classified as mildly abrasive, with a value of under 200,
21 products fell into the intermediate abrasiveness category, with
dentin abrasion values ranging between 200 and 400, and seven
products fell into the harsh abrasiveness category with dentin
abrasion values over 400.
Over and above as well as independently of the foregoing
considerations with respect to the cleaning and polishing
properties of toothpastes, efforts have long been made to embody in
toothpastes ingredients which inhibit or reduce dental caries.
Possibly the most widely used caries reducing or inhibiting
ingredients in toothpastes are those which provide a fluoride ion
as, for instance, stannous floride. A significant problem which has
been encountered in incorporating fluoride ions, through the use of
fluorine-containing inorganic compounds, into toothpastes has been
the fact that the abrasive or polishing ingredient or ingredients
of the toothpaste reacts with the fluorine-containing inorganic
compounds, usually slowly or gradually and over a period of time,
which may be weeks or months, to inactivate said
fluorine-containing compounds, apparently by forming insoluble
compounds which do not ionize to release fluoride ions. Such
insoluble compounds have no caries reducing or inhibiting
properties in that they do not bring about desired enamel hardening
effects on the tooth enamel. Hence, such toothpastes have poor
storage properties in that they lose their intended caries reducing
or inhibiting effects over a period of time.
Certain procedures have heretofore been evolved, as shown in
various prior art patents and publications, to meet the aforesaid
problem associated with incorporating fluorine-containing compounds
into toothpastes. Thus, in U.S. Pat. No. 2,876,166, it is shown
that such abrasive or polishing agents as calcium orthophosphate,
if heat treated to convert it into calcium pyrophosphate or certain
other molecularly dehydrated calcium phosphates, will, when used as
the abrasive or polishing agent in toothpastes containing
fluorine-containing compounds, make for much greater availability
of fluoride ions than if the conventional non-heat treated calcium
orthophosphate was used. Other approaches designed to meet this
problem are disclosed in U.S. Pat. Nos. 3,227,617 and
3,308,029.
Sodium fluoride is perhaps one of the most difficult
fluorine-containing dental caries inhibiting agents to effectively
incorporate into a toothpaste in which the abrasive or polishing
agent is a calcium compound whereas stannous fluoride does not,
generally speaking, present as great difficulties. This appears to
be due to the fact that sodium fluoride is entirely ionic, whereas,
in stannous fluoride, the fluoride bond has a substantial covalent
character. Nevertheless, certain special toothpaste compositions
have been suggested utilizing sodium fluoride in conjunction with
certain metaphosphates wherein the sodium fluoride is reasonably
stable and is capable of inhibiting dental caries by reducing
enamel solubility.
It has been discovered, in accordance with the present invention,
that certain combinations of ingredients comprising abrasive
agents, fluorine-containing compounds, and a water-soluble
polyoxyalkyleneglycol, without any mineral oil or vegetable or
animal triglyceride oils, in a toothpaste exhibit improved
properties with respect to the matter of stability of the
fluorine-containing compounds over prolonged periods of time. The
compositional environment of the toothpastes of the present
invention is of a character such that a wide variety of
fluorine-containing compounds maintain their stability to a
substantial extent in the presence of a wide variety of abrasive or
polishing agents. In addition, where mild abrasives are utilized,
the toothpastes of the present invention also surprisingly exhibit
enhanced cleaning and luster-imparting properties in relation to
tooth surfaces. While toothpaste formulations can be made in
accordance with our invention which contain substantially no water,
our invention also contemplates toothpaste formulations which
contain proportions of water, generally up to about 10%, while
still maintaining excellent stability of the fluorine-containing
compound or compounds.
The toothpaste compositions of the present invention contain a very
substantial, generally a major, proportion of one or more abrasives
based on the weight of the solids of the toothpaste formulation,
and, generally, at least 20%, by weight of the total of the liquid
ingredients of the toothpaste formulation, of one or more
polyoxyalkyleneglycols described in detail below. While, in certain
cases, polyoxyalkyleneglycols may constitute the liquid
ingredients, and the total liquid ingredients, of the toothpaste,
they may constitute only a part of the liquid ingredients of the
toothpaste formulation, not less than 20% by weight of said liquid
ingredients and, better still, from 35% to 60% of the total weight
of the liquid ingredients of the toothpaste. In other cases, the
polyoxyalkyleneglycols utilized are semi-solid or solid at room
temperature. Based on the weight of the finished toothpaste, the
polyoxyalkyleneglycols will usually most desirably comprise from
about 20% to about 30% although the percentages may be somewhat
lower, usually not below about 15%, or somewhat higher, usually not
more than 45%.
Various of them can be represented by the formula
HO--Alk--O--(Alk--O).sub.n H
where Alk is an alkylene radical containing from 2 to 4 carbon
atoms, namely, ethylene, propylene or butylene, especially
ethylene, and n is an integer such that the average molecular
weight of the polyoxyalkyleneglycol is at least 200 and so that the
polyoxyalkyleneglycol is reasonably water-soluble or is soluble in
the liquid ingredients of the toothpaste formulation, hereafter,
for convenience, encompassed by the term "water-soluble." In the
case of the polyoxyethyleneglycols, the subscript n is at least 4
and can be materially greater than 4 and, indeed, up to the point
where the polyoxyethyleneglycol is a solid at room temperature.
Illustrative polyoxyalkyleneglycols which are useful in the
production of toothpastes in accordance with our invention are
polyoxyethyleneglycols having average molecular weights of about
200, 350, 400, 500, 600, 700, 800, 900 and 1,000 and, as stated
above, still higher in certain cases. Mixtures of the aforesaid
polyoxyalkyleneglycols can also be utilized. Furthermore,
polyoxyalkyleneglycols can be used in which there are present
ethoxy and propoxy groups, or ethoxy and butoxy groups, or propoxy
and butoxy groups, or all three of such groups as, for instance, 1
mole of tetraethyleneglycol adducted with 1 mole of propylene oxide
and 1 mole of polyoxyethyleneglycol 400 adducted with 1 mole of
propylene oxide. Particularly satisfactory are
polyoxyethyleneglycols having average molecular weights between
about 600 and about 800, or 650 to 750, those having an average
molecular weight of about 700 being especially satisfactory. It may
be noted that the viscosity, in centipoises and measured at
70.degree.F, of a polyoxyethyleneglycol which has an average
molecular weight of about 600, (Polyethyleneglycol 600), is about
11,000, and it is a semi-solid at 70.degree.F or room temperature;
and that a polyoxyethyleneglycol having an average molecular weight
of 700 or higher is a solid at 70.degree.F or room temperature.
It is, at times, desirable to include with said latter
polyoxyethyleneglycols, in any given toothpaste formulation made in
accordance with the present invention, a smaller proportion of
higher polyoxyethyleneglycols, such as those of an average
molecular weight of about 2,000 to about 6,000, generally in the
range of about 5 to 12% by weight of the toothpaste. The
polyoxyalkyleneglycols utilized pursuant to the present invention
are not surfactants or surface active agents in the sense of which
such terms are commonly used in the art. For purposes of the
present invention, the polyoxyalkyleneglycols employed in the
practice of the present invention will, in a 1% solution in water
at 25.degree.C, not reduce the surface tension of water to below 45
dynes/cm.
The dry ingredients of the toothpastes of the present invention
contain one or more abrasives such as precipitated calcium
carbonate, dicalcium phosphate dihydrate, dicalcium phosphate
anhydrous, dibasic calcium phosphate, tribasic calcium phosphate,
calcium pyrophosphate, calcium sulfate, hydrated alumina, silica,
insoluble sodium metaphosphate, and the like, the abrasive
constituting the major proportion of the total of the dry
ingredients or the major proportion of the total of the solids of
the toothpaste formulation. The RDA values of the abrasives
selected are desirably not above about 400, and should not be in
excess of 200 for best results in accordance with the present
invention. Particularly satisfactory is dicalcium phosphate
dihydrate with an RDA value of about 125 to 150. The RDA value of
the finished toothpaste, in its particularly advantageous
embodiments, is not in excess of 200 and, better still, is in the
range of about 90 to about 150.
The fluorine-containing or fluoride compounds which can be used in
accordance with the present invention are, per se, known to the art
for use in reducing or inhibiting dental caries. They comprise,
generally speaking, fluorine-containing compounds which normally
dissociate to yield fluoride ions in aqueous solution, and they
include, among others, such inorganic compounds as alkali metal
fluorides such as sodium fluoride, potassium fluoride and lithium
fluoride, stannous fluoride, stannous chlorofluorides, sodium
monofluorophosphate and stannous fluorozirconate. They are shown in
such U.S. Pats. as Nos. 2,839,448; 2,876,166; 2,946,725; 3,227,617;
3,227,618; 3,226,867; 3,266,996 and 3,308,029, the disclosures with
respect to said fluorides being incorporated herein by reference.
Especially satisfactory are stannous fluoride, titanium
tetrafluoride and tin (II) octafluorozirconate. The proportions
thereof are, in all cases, small and will usually be employed in
amounts to provide at least 0.01%, by weight, of ionizable fluoride
and generally not more than 0.4%, by weight, total fluorine. In the
case of stannous fluoride, for instance, the amount thereof will be
in the range of about 50 to 3,000 parts per million based on the
weight of the toothpaste with a good average being about 1,000 to
about 1,500 parts per million. The percentages are not critical and
are indicated in the foregoing patents. The fluorine-containing
compounds are a part of the dry ingredients of the toothpaste
formulation.
In addition, commonly it is the practice to include one or more
detergents or surfactants in the toothpaste formulation and where
such is a normally solid product, or contains solids, as will
usually be the case, it is considered as constituting a dry
ingredient of the toothpaste formulation. COmmonly used detergents
or surfactants include, by way of illustration, soaps, sodium
lauryl sulfoacetate, sodium lauryl sulfate, sulfocolaurate, sodium
salts of sulfated monoglyceride (of coconut oil fatty acids), and
sodium N-lauroyl sarcosinate.
Other normally solid ingredients which, commonly, are incorporated
into toothpastes are binders, which are usually hydrophilic
colloids. Among such binders are, for instance, gum arabic, ghatti,
gum karaya, gum tragacanth, Irish moss, (Na) alginates, bentonite,
Veegum, methyl cellulose and sodium carboxymethylcellulose. In a
limited aspect of the present invention, it has been found that
metallic, particularly aluminum, soaps of fat-forming fatty acids,
especially aluminum stearate, are exceptionally satisfactory,
aluminum soaps, such as aluminum octoate or aluminum stearate
appearing to coact with the polyoxyalkyleneglycols to further
enhance the polish and luster of the brushed teeth, and also
functioning effectively to stabilize the paste character of the
toothpaste at the elevated temperatures which are at times
encountered in shipping and storage of the toothpastes. Where
employed, they will usually be used in a proportion of about 1 to
about 12% by weight of the toothpaste. Where aluminum soaps are
included in the toothpaste formulations of the present invention,
care must be exercised, if water is to be incorporated into the
toothpaste formulation, that too much water be not employed since
it may destroy the desired gel structure imparted by the aluminum
soaps. In any event, the binder selected must be one which will
swell in the toothpaste mixture of ingredients into which it is
incorporated.
The liquid ingredients of the toothpastes of the present invention,
in addition to such water-soluble polyoxyalkyleneglycols as may be
normally liquid at room temperature, desirably also include one or
more of glycerin, propylene glycol and sorbitol solutions, or
mixtures of the same, which are utilized for, in addition to their
well-known humectant properties, their ability to improve taste and
mouth feel. In certain cases, it may be desirable to include small
proportions of water which, generally, will not be in excess of
about 5% but, in certain cases, may be appreciably greater, of the
weight of the liquid ingredients of the formulation, in the
toothpaste formulations of our invention. The water serves mainly
to counteract or reduce possible adverse tastes that may otherwise
tend to be imparted to the toothpaste by particular
polyoxyalkyleneglycols which are utilized in said toothpastes.
Various supplemental ingredients can, of course, be incorporated
into the toothpastes to obtain particular effects and they may be
of liquid or solid character. Illustrative of such supplemental
ingredients are perfumes, dyes or other colorants, chloroform or
flavoring chloroform, and enzymes, etc.
The following examples are illustrative of toothpastes in
accordance with the present invention. It will be understood that
numerous other toothpastes can be made following the guiding
principles and teachings disclosed herein. Unless otherwise
specified, all parts are in terms of weight.
Example A ______________________________________ Parts
Polyoxyethyleneglycol 4000 5 Dicalcium Phosphate Dihydrate 40
Aluminum Stearate 5 Sodium Saccharin 0.75 Methyl "PARABEN" 0.18
(methyl ester of para- hydroxy benzoic acid) Propyl "PARABEN" 0.05
(propyl ester of para- hydroxy benzoic acid) "MAPROFIX"563 1.5
(anhydrous sodium lauryl sulfate) Flavoring 1 Total 53.48
______________________________________
Individual Examples are made by combining, in each case, the
aforesaid composition with 46.52 parts of the identified
fluorine-containing compound, polyethyleneglycol of average
molecular weight about 700, and 96% glycerin in the indicated
parts:
__________________________________________________________________________
THE BALANCE (46.52%) IS COMPRISED OF: Fluoride 96% 1000ppm F Salt =
PEG700 Glycerin
__________________________________________________________________________
1. Sodium Na.sub.2 PO.sub.3 F 0.76 22.88 22.88 Monofluorophosphate
2. Stannous SnF.sub.2 0.40 23.06 23.06 Fluoride 3. Sodium Fluoride
NaF 0.20 23.16 23.16 (= 900 ppm F.sup.-) 4. Calcium CaPO.sub.3 F
0.943 22.789 22.789 Monofluorophosphate 5. Potassium K.sub.2
PO.sub.3 F 0.962 22.779 22.779 Monofluorophosphate 6. Titanium
TiF.sub.4 0.163 23.179 23.179 Tetrafluoride 7. Potassium KPO.sub.2
F.sub.2 0.40 23.06 23.06 Difluorophosphate 8. Octafluorozirconotin
ZrF.sub.4.2SnF.sub.2 0.332 23.094 23.094
__________________________________________________________________________
Any suitable procedure can be used to produce the toothpaste from
the above formulation. One suitable way is to place the
polyoxyethyleneglycol 4000, the polyoxyethyleneglycol 700 and the
glycerin in a mixer and heat to about 55.degree. to 60.degree.C to
provide a liquid mixture. The mixture is transferred to another
container and allowed to cool to about 35.degree.C under conditions
of mixing. The dicalcium phosphate dihydrate, the sodium saccharin,
the fluorine-containing compound, the methyl PARABEN and the propyl
PARABEN are then blended in, with stirring, then the aluminum
stearate is added, a vacuum of about 25 inches is drawn and mixing
is effected at high speed for about 20 minutes after which the
MAPROFIX 563 is added. The mixing is continued under stirring for
about 3 to 5 minutes. The temperature rises to about 50.degree.C
during the two last-mentioned mixing steps. The flavoring is mixed
in, and then the mixture is pumped into a large tank from which it
is filled into conventional toothpaste containers.
Other well known mixing procedures for producing toothpastes can be
employed, as such or with minor variations. Thus, for instance, the
binder, previously wetted with the humectants, is admixed, under
slight heating if desired, with and dispersed in the remaining
liquid portion of the toothpaste formulation (except for the
flavoring) containing the sodium saccharin and such preservative as
may be utilized. The resulting gel is then admixed, in a suitable
mixer, with a premixture of the abrasive and the
fluorine-containing compound, said premixture being added gradually
to the gel, until homogeneity is obtained. Finally, the flavor and
the detergent are added and mixed uniformly through the mass. The
latter may then be milled, deaerated, and filled into toothpaste
tubes.
______________________________________ Example B
______________________________________ Parts Polyoxypropyleneglycol
700 23.25 Dicalcium Phosphate Dihydrate 41.5 Glycerin 23.25 Lauryl
Sodium Sulfate 2 Carboxyvinyl polymer ("Carbopol 934") 1 Stannous
Fluoride 0.5 Sodium Saccharin 0.5 Water 7.5 Flavoring as desired
Example C ______________________________________ Parts
Polyoxyethyleneglycol 600 22.3 Aluminum Hydroxide Gel (20% water)
52.85 Glycerin 23 Titanium Tetrafluoride 0.15 Lauryl Sodium Sulfate
1 Sodium Saccharin 0.1 ______________________________________
Toothpaste compositions made in accordance with the present
invention exhibit excellent stability of the fluorine-containing
compositions. Thus, in the following Table I tests are shown of
toothpastes made as described in Example A, using various
fluorine-containing compounds in varying proportions and over
varying periods of storage at different illustrative temperatures.
The ionic fluoride levels in the cases of SnF.sub.2, NaF, TiF.sub.4
and ZrF.sub.4.2SnF.sub.2 were excellently maintained with
relatively minor losses over a period of 26 weeks. In the cases of
KPO.sub.2 F.sub.2, Na.sub.2 PO.sub.3 F and K.sub.2 PO.sub.3 F, the
ionic fluoride levels dropped off appreciably, particularly at the
higher temperatures but, even here, a reasonable level was
maintained. In this connection, it may be pointed out that
conventional dentifrices containing, for instance, sodium fluoride,
and dicalcium phosphate dihydrate as the abrasive, show essentially
no ionic fluoride after even as low a storage period of 24 hours;
and where the toothpaste contains stannous fluoride, and calcium
pyrophosphate as the abrasive, there is commonly an approximately
50% loss of ionic fluoride over a period of about 6 months.
TABLE I
__________________________________________________________________________
Stability of Various Fluorides In Dentifrices of Example A PPM
F.sup.- vs WEEKS STORAGE % = 1000 Storage Salt ppm F.sup.- 0 4 8 16
26 Temp .degree.C
__________________________________________________________________________
SnF.sub.2 in 0.4 (1000)* -- 800 750 825 22 lined (1000)* -- 875 750
825 37 Pb tubes (1000)* -- 925 575 -- 50 SnF.sub.2 in 0.4 903 890
873 903 -- 22 plastic 903 934 945 935 -- 37 laminated 903 875 900
865 -- 50 tubes NaF 0.2 (900)* -- -- 855 810 22 (= 900 (900)* -- --
765 675 37 ppm F.sup.-) (900)* -- -- 765 -- 50 TiF.sub.4 0.163 1043
982 982 -- 926 22 1043 920 920 -- 890 37 1043 920 859 -- -- 50
KPO.sub.2 F.sub.2 0.4 850 800 743 663 -- 22 850 650 538 368 -- 37
850 300 280 415 -- 50 ZrF.sub.4.2SnF.sub.2 0.332 889 898 852 -- --
22 889 -- 852 -- -- 37 889 898 855 -- -- 50 Na.sub.2 PO.sub.3 F
0.76 895 658 802 540 -- 22 895 421 605 474 -- 37 895 342 579 263 --
50 K.sub.2 PO.sub.3 F 0.962 707 665 593 541 -- 22 707 468 364 457
-- 37 707 426 208 218 -- 50
__________________________________________________________________________
*Initial value based on formula; not determined by analytical
method.
It is generally recognized that ionically stable fluoride in
dentifrices acts to make tooth enamel more resistant to attack by
acids. Tests were run in vitro with illustrative toothpastes of the
present invention and enamel solubilities were determined by a
composite procedure based upon those reported by Rae & Clegg,
J. Dent. Res. 24, 235-7 (1945); Suess & Fosdick, J. Dent. Res.
30, 177-81 (1951); Muhler et al., J. Dent. Res. 29, 182-193 (1950).
The method used for preparing powdered tooth enamel was reported bu
Manly & Hodge and is based on a flotation process which
separates the heavier enamel material from the dentin and other
debris. In essence, powdered tooth enamel is exposed to a lactate
buffer and the amount of dissolved calcium and/or phosphorus
measured quantitatively. The percent reduction in enamel solubility
is calculated from the difference between calcium and/or phosphorus
dissolved from a treated sample compared to that from an untreated
sample. Treatment consists of exposing 100 mg of powdered enamel to
a slurry of 3 ml of water and 3 g of fluoride dentifrice for 10
minutes. The treated enamel is separated from the dentifrice
materials and exposed to a lactate buffer.
In the following Table II, the results of such tests are shown
using a toothpaste made according to Example A, employing stannous
fluoride. All numbers, with the exception of 7.5 for the toothpaste
base, are significantly different from the control values. The 44
week sample at 37.degree.C, containing 0.4% stannous fluoride,
shows an excellent reduction of 25% in enamel solubility; the 8
week sample at 50.degree.C, containing 0.4% stannous fluoride,
which usually corresponds generally to one year room temperature
stability, shows an excellent reduction of 38% in enamel
solubility.
TABLE II ______________________________________ Enamel Solubility
Reduction Average % % P .times. 10.sup.-.sup.2 % Ca .times.
10.sup.-.sup.2 Reduction ______________________________________
Control - Untreated 6.02 12.48 0 Enamel Powder Dentifrice Base 5.57
11.58 7.5 Without F.sup.- * 0.4% SnF.sub.2 Solution = 1000 ppm
F.sup.- 4.85 10.05 19 0.2% SnF.sub.2 Solution = 500 ppm F.sup.-
5.02 10.35 17 PEG Dentifrice + 0.4% SnF.sub.2 3.68 7.31 40 Aged 8
wks.sup.2, 22.degree.C PEG Dentifrice + 0.4% SnF.sub.2 * 3.77 7.60
38 Aged 8 wks, 50.degree.C PEG Dentifrice + 0.4 SnF.sub.2 * 4.41
9.57 25 Aged 44 wks, 37.degree.C
______________________________________ * Diluted 50% with H.sub.2 O
solution for treatment.
As indicated above, the toothpastes of the present invention
possess the advantage of maintaining to a substantial extent, over
prolonged periods of time, fluoride ion activity, and, in their
particularly advantageous, though limited, embodiments, the
additional advantage of improved cleaning and polishing properties.
The latter advantage is evidenced by comparisons of toothpastes
using low RDA value mild abrasives, for instance, 125 to 175, with
conventional commercial toothpastes using high RDA value strong
abrasives, for instance, 500 to 600, in which case the average
cleaning scores of the toothpastes of the present invention are at
least as good as, and the strain-removing properties are superior
to, those which used the high RDA value abrasives.
It heretofore has been known to prepare and commercially market
toothpastes containing, in addition to (a) a major proportion of an
abrasive, based on the weight of the dry ingredients of the
toothpaste, (b) liquid ingredients comprising a humectant, and a
substantial amount of water, generally of the order of about 40 to
45%, and also containing about 11% of a polyoxyethyleneglycol of a
molecular weight of the order of about 400, said percentages being
by weight of the (b) or liquid phase of the toothpaste (about 5.5%
by weight of the toothpaste). The apparent function of the
polyoxyethyleneglycol in the foregoing known toothpastes is to
assist in solubilizing the flavor constituents used in the
toothpaste formulation. In any event, such proportions of
polyoxyethyleneglycol are ineffective to achieve a cleaning
enhancement or polishing effect on the teeth and, as stated above,
a minimum of almost twice that quantity is required. Indeed, it is
particularly advantageous, in the practice of the present
invention, as has been pointed out above, that the
polyoxyethyleneglycol constitute from about 30 to 60% of the total
weight of the liquid ingredients of the toothpaste. Moreover, such
prior practice does not deal with and provides no teaching of the
stabilization of fluorine-containing compounds in the presence of
abrasive or polishing agents.
It has also heretofore been known, as shown in U.S. Pat. No.
2,501,145, to produce nonaqueous toothpastes containing perborate
which, in use, in the presence of water, release oxygen. To
increase the stability of said toothpastes against premature
release of oxygen, aldehydic inactivating agents and
polyoxyethyleneglycols of a molecular weight in the range of 300 to
2,000 are included in the toothpaste compositions,
polyoxyethyleneglycols of viscous character being included to
provide a suitable base for the toothpaste. Furthermore, it has
been known, as shown in U.S. Pat. No. 3,250,680, to produce
nonaqueous toothpastes of the self-heating type containing finely
divided solid adsorbent materials capable of adsorbing water
exothermically, such as silica gel, and a liquid nonaqueous vehicle
which is inert to said adsorbent particles, such as
polyoxyethyleneglycols and polyoxypropyleneglycols which melt at
temperatures no higher than 75.degree.C, such vehicles being
employed in small proportions in the toothpaste, generally of the
order of less than 3%. These prior known disclosures provide no
teaching nor suggestion of the present invention.
It has, furthermore, heretofore been disclosed, as shown in U.S.
Pat. No. 3,574,824, to prepare anhydrous toothpastes containing, as
essential ingredients, in certain specified proportions, certain
oils of a defined viscosity, such oils being mineral oils,
thickened light liquid petrolatum, and vegetable triglyceride oils;
a polyethylene glycol composition having a specified critical range
of viscosities (about 2200 to 3400 cps at 70.degree.F) and
comprising a combination of polyethylene glycols having molecular
weights ranging from about 550 to 6,000; certain non-ionic
emulsifiers; certain binding agents; and mannitol and/or inositol
as a compound having a negative heat of hydration; with or without
such toothpaste abrasives as aluminum hydrate, calcium sulfate, and
aluminum silicate, and with or without various supplemental
ingredients including, among others, enzymes, bleaching agents, and
fluorides such as sodium fluoride, potassium fluoride, stannous
fluoride as well as certain other fluorides. Efforts to produce
toothpastes according to the disclosures in said patent, notably
primary Example 1 thereof, utilizing as the toothpaste abrasive,
various commercial hydrated aluminas, or a mixture of hydrated
alumina and KAYOPOLITE S.F., resulted in compositions which were
very dry and stiff and almost impossible to extrude from tubes.
When the abrasives of said Example 1 were replaced to the
toothpaste abrasive dicalcium phosphate dihydrate, no paste was
obtained but, rather, a dry, lumpy mixture which could not be
packaged in a tube in the manner of a toothpaste and, as stated,
did not constitute a paste.
The term "toothpaste", as used in the claims, will be understood to
mean toothpastes which are not of the oxygen-liberating type.
* * * * *