U.S. patent number 3,608,067 [Application Number 04/797,242] was granted by the patent office on 1971-09-21 for dentifrice compositions containing insoluble salts of alkylene phosphonic acids.
This patent grant is currently assigned to Monsanto Company. Invention is credited to Riyad R. Irani.
United States Patent |
3,608,067 |
Irani |
September 21, 1971 |
**Please see images for:
( Certificate of Correction ) ** |
DENTIFRICE COMPOSITIONS CONTAINING INSOLUBLE SALTS OF ALKYLENE
PHOSPHONIC ACIDS
Abstract
Dentifrice composition containing as the primary polishing agent
a substantially water-insoluble salt of an alkylene phosphonic acid
such as the calcium salt of an alkylene diphosphonic acid having
the formula, e.g.
Inventors: |
Irani; Riyad R. (Mentor,
OH) |
Assignee: |
Monsanto Company (St. Louis,
MO)
|
Family
ID: |
21624407 |
Appl.
No.: |
04/797,242 |
Filed: |
February 6, 1969 |
Foreign Application Priority Data
Current U.S.
Class: |
424/49;
424/52 |
Current CPC
Class: |
A61Q
11/00 (20130101); A61K 8/55 (20130101) |
Current International
Class: |
A61K
8/55 (20060101); A61K 8/30 (20060101); A61Q
11/00 (20060101); A61k 007/16 () |
Field of
Search: |
;424/49-58 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Huff; Richard L.
Claims
What is claimed is:
1. A toothpaste composition comprising as the primary polishing
agent a member selected from the group consisting of (1) a
substantially water-insoluble salt selected from the group
consisting of calcium salt, magnesium salt, zinc salt, aluminum
salt and mixtures thereof of alkylene diphosphonic acid having the
formula:
wherein n is an integer from 1 to 20, X is selected from the group
consisting of H and a lower alkyl radical of one to four carbon
atoms and Y is selected from the group consisting of H, OH, and a
lower alkyl radical of one to four carbon atoms; and (2) a hydrate
of said salts, the particles of said polishing agent having a mean
diameter of from about 5 microns to about 40 microns, said
polishing agent having a dentin abrasion value of less than 500,
and said polishing agent being present in said dentifrice
composition in an amount of from about 20 weight percent to about
60 weight percent based on the weight of the dentifrice
composition.
2. A composition according to claim 1, wherein the composition is a
toothpaste.
3. A dentifrice composition as set forth in claim 1 wherein said
polishing agent is a salt selected from the group consisting of a
calcium salt of 1-hydroxy, 1-ethylidene diphosphonic acid and a
hydrate thereof.
Description
The present invention generally relates to dentifrice compositions
containing novel polishing agents and more particularly relates to
improved dentifrice compositions containing such novel polishing
agents along with stannous tin and fluoride in an ionized state.
The present invention further relates to dentifrice compositions
containing, as an abrasive therein, a novel ingredient which is
compatible with the aforementioned stannous tin and fluoride ions
which also may be present in said compositions. The present
invention is more specifically directed to dentifrice compositions
containing the aforementioned novel ingredient which has a
polishing and cleansing effect and is further characterized, when
said composition is used in oral hygiene, from deleterious abrasive
or scratching action of tooth enamel and dentin.
In the field of oral hygiene, a satisfactory dentifrice should have
a cosmetic effect on the teeth whereby the daily use of said
dentifrice keeps said teeth in an essentially stain-free (or
white-appearing) state. Such a dentifrice should also have a
functional effect on the teeth and mouth, keeping them clean and
free from food debris, thereby aiding the prevention of tooth
decay. In order to achieve these aforementioned end results, it is
generally necessary to brush the teeth with a dentifrice
composition containing a cleaning agent which is generally referred
to in the art as an abrasive. The main purpose of this cleaning
agent is to aid in the removal from the tooth surface of tightly,
adherent pellicle film which in many persons contains pigments
which color said film (and thus the teeth) brown or yellow.
Furthermore, this cleaning agent should remove this pellicle film
with a minimum of abrasion of the underlying tooth material. The
tooth surface is covered with what is commonly known as enamel
which covers much of the exposed tooth surface and is a relatively
hard material which, generally speaking, is not materially affected
by polishing agents. However, the softer dentin, which may be
exposed by receding gums, is a major problem and concern in
selecting an ideal or appropriate cleaning agent. Thus, the agent
selected must be one which effects the maximum removal of the
pellicle film with the minimum abrasion of the dentin.
In addition to the function of the dentifrice in maintaining oral
hygiene or cleanliness, there is also merit in including an
ingredient which acts specifically to reduce tooth decay. In the
past 15 years, extensive laboratory and field experimentation has
been stimulated by the discovery of the beneficial effect of
fluoride in drinking water or topically applied to the tooth
surface and has subsequently led to the development of dentifrices
containing stannous fluoride and, more recently, sodium
monofluorophosphate. The successful effect of these fluoride (and
stannous ions in the case of stannous fluoride) containing
dentifrices (which include, respectively, F.sup.- and PO.sub.3
F.sup.-.sup.-.sup.- ions in solution) in reducing the incidence of
caries has been established by statistical evidence. Such
effectiveness is substantiated as exemplified in the body of
scientific literature hereinafter set forth, and which supports the
conclusion that the use of dentifrices containing a source of
fluoride ions (which term, as used herein, includes F.sup.-,
PO.sub.3 F.sup.-.sup.-.sup.-, and other fluoride ion complexes)
reduces the rate at which dental caries are formed; note J. C.
Muhler, et. al., Journal of Dental Research, Vol. 33, page 606,
(1954); J. C. Muhler, et. al., Journal of the American Dental
Association, Vol. 50, page 163 (1955); J. C. Muhler, et. al.,
Journal of Dental Research, Vol. 35, page 49 (1956); and W. A.
Jordon et al., Journal of the American Dental Association, Vol. 54,
page 589 (1957). It is also the opinion of some scientists that the
presence of stannous ions with fluoride ions gives a more effective
paste than fluoride alone; note J. C. Muhler, et al., Journal of
American Dental Association, Vol. 51, page 556, (1955).
One major problem in the manufacture and widespread distribution of
such dentifrices is to maintain the fluoride ions (and stannous
ions when using, for example, SnF.sub.2) over a period of months,
in substantially an available form, and in such form thus be
available for the treatment of the teeth in a manner heretofore set
forth. The main reason for this reduction of availability of such
ions is the reaction thereof with the cleaning agent, i.e. the
polishing agent or abrasive ingredient, to form complexes which are
nonreactive with the tooth surface.
While the prior art has generally recognized this latter problem of
maintaining the fluoride ions (and stannous ions) in available form
when incorporated in a dentifrice composition, there has also been
a substantial need in the dentifrice art for the provision of a
dentifrice which contains a cleaning agent or abrasive material
having a low dentin abrasion value, and which abrasive is also
compatible, i.e. does not detrimentally react with the F.sup.-,
PO.sub.3 F.sup.-.sup.-.sup.-, Sn.sup.+.sup.+, with said dentifrice
composition containing the ionic anticaries agent such as stannous
fluoride or sodium monofluorophosphate.
Accordingly, it is one object of the present invention to provide a
dentifrice composition containing a novel polishing agent.
It is another object of the present invention to provide a
dentifrice containing fluoride ions (and stannous ions, if using
SnF.sub.2) which do not react detrimentally with the abrasive or
cleaning agent and thus remain available for treatment of the tooth
surface on use.
It is another object of the present invention to provide an
abrasive material which is effective in removing pellicle films
from the teeth and which causes a minimum of abrasion to the tooth
dentin.
Further objects and advantages of the present invention will become
apparent from the subsequent description and the appended
claims.
In general, the present invention provides a dentifrice composition
containing ingredients usually employed in toothpowders or
toothpastes and an abrasive or polishing agent comprising a
substantially water-insoluble salt of an alkylene-phosphonic acid,
which may be used as the sole polishing agent or in combination
with minor amounts of other dental abrasives or polishing agents,
such as dicalcium orthophosphate dihydrate, insoluble sodium
metaphosphate, dental abrasive grade of calcium pyrophosphate and
the like, and mixtures thereof.
A particularly preferred class of substantially water-insoluble
salts of alkylene phosphonic acids which may be employed in the
dentifrice compositions are substantially water-insoluble salts of
alkylene diphosphonic acids having the formula:
wherein n is an integer from 1-20 (preferably 2-10), X represents H
or lower alkyl (e.g. one-four carbon atoms) and Y represents H, OH
or lower alkyl (e.g. one-four carbon atoms). The most suitable
salts of these acids for use in the dentifrice compositions of this
invention are the calcium, barium, magnesium, zinc and/or aluminum
salts, and these include partial salts, that is, those partial
salts in which one or more of the hydrogen atoms of the (OH) groups
in the acids of the above formula have not been replaced by such
metal atoms, but which partial salts are still sufficiently
insoluble in water to have utility as polishing agents in the
dentifrice compositions, and also include salts in which one or
more of the hydrogen atoms of the (OH) group in the acids of the
above formula have been replaced by sodium or ammonium ions, but
are still insufficiently insoluble in water to have utility as
polishing agents in the dentifrice compositions. Also included are
the hydrates of such salts. Acids of the above formula may be
prepared by procedures described in U.S. Pat. No. 3,297,578 issued
to Marvin M. Crutchfield and Riyad R. Irani.
Some specific examples of the aforedescribed general class of
substantially water-insoluble salts of alkylene diphosphonic acids
are the following:
l. Calcium or magnesium salts of methylene diphosphonic acid -
specifically CaH.sub.2 CH(PO.sub.3).sub.2 and MgH.sub.2 CH.sub.2
(PO.sub.3).sub.2, and hydrates thereof;
2. Calcium or magnesium salts of 1-hydroxy propylidene diphosphonic
acid - (OH).sub.2 (O)PC(OH)(CH.sub.2 -CH.sub.3)P (O)(OH).sub.2,
specifically CaH.sub.2 C(OH) (CH.sub.2 -CH.sub.3)(PO.sub. 3).sub.2
or MgH.sub.2 C(OH)(CH.sub. 2 -CH.sub.3)(PO.sub.3).sub.2, and
hydrates thereof; and
3. Calcium or magnesium salts of hexamethylenediphosphonic acid --
(OH).sub.2 (O)PCH.sub.2 (CH.sub.2).sub.4 CH.sub.2 P(O)(OH).sub.2,
specifically CaH.sub.2 (PO.sub.3)CH.sub.2 (CH.sub.4).sub.4 CH.sub.2
(PO.sub.3) or MgH.sub.2 (PO.sub.3)CH.sub.2 (CH.sub.2).sub.4
CH.sub.2 (PO.sub.3), and hydrates thereof; and
4. Calcium or magnesium salts of 1-hydroxy ethylidene diphosphonic
acid -- (OH).sub.2 (O)PC(OH)(CH.sub.3)P(O)(OH).sub.2, specifically
CaH.sub.2 (PO.sub.3)C(OH)(CH.sub.3)(PO.sub.3).sup.. 2H.sub.2 O or
MgH.sub.2 (PO.sub.3)C(OH)(CH.sub.3)(PO.sub.3).sup.. 2H.sub.2 O or
the corresponding anhydrous salts or different hydrates of such
salts.
Another embodiment of the present invention provides a dentifrice
composition containing (a) one or more of the aforedescribed
substantially water-insoluble salts of the alkylene phosphonic
acids; and (b) a water-soluble, innocuous (as hereinafter defined),
fluoride salt such as water-soluble, fluorine-containing organic
salts; water-soluble fluorine-containing inorganic salts, and
mixtures thereof. If desired, a water-soluble, innocuous, stannous
tin salt of a mineral acid may be added to the above-described
composition in order to provide stannous ions (if SnF.sub.2 is not
the fluoride salt) or an excess of stannous ions (even if SnF.sub.2
is used). It is to be noted that the fluorides included under item
(B) and said tin salt can represent either the same compound, for
example, stannous fluoride, or different compounds, for example,
(b) can be sodium fluoride and such additional stannous tin salt
can be stannous fluoride.
The adjective "innocuous," as used herein in regard to fluoride and
stannous compounds means a compound which is substantially nontoxic
in the proportions used, or is not highly colored, or is not
otherwise objectionable for use in a dentifrice composition.
The substantially water-insoluble salts of alkylene phosphonic
acids have a satisfactory degree of polishing and cleansing action
and at the same time they are sufficiently nonabrasive to minimize
scratching or other deleterious effects on the enamel or cementum
of the teeth. Such salts usually have a dentin abrasion value, as
hereinafter defined, of less than 500, usually from 200 to about
350. A polishing agent having this low dentin abrasion value is
still effective in its cleansing action when applied in oral
hygiene but, on the other hand it does not detrimentally abrade the
tooth surface. Dicalcium orthophosphate dihydrate, a commonly used
polishing agent in dentifrices, usually has a dentin abrasion value
of about 250-350.
The dentin abrasion value is a relative number indicating the
degree of abrasiveness of a material. The procedure for the
evaluation of this abrasiveness is the method of Grabenstetter et
al. described in the Journal of Dental Research, Vol. 17, No. 6,
Nov.-Dec. 1958, pages 1,060-1,068; note also U.S. Pat. No.
2,876,168. Briefly, the cleaning agent or abrasive is determined to
have a certain dentin abrasion value after it has been utilized in
the mechanical brushing of radioactive dentin from extracted human
teeth.
In general, the aforementioned substantially water-insoluble salts
of alkylene phosphonic acids (as polishing agents) constitute from
about 0.5 percent to about 96 percent by weight of the total weight
of the dentifrice composition. When such polishing agents are being
utilized in a dentifrice composition such as toothpaste, it is
preferred that they be present in an amount of from about 20
percent to about 60 percent by weight of the total weight of the
dentifrice composition. On the other hand, when it is desired to
prepare a toothpowder, it is preferred that such polishing agents
be present in an amount of from about 60 percent to about 96
percent by weight based on the total weight of the dentifrice
composition.
It is preferred that the polishing agents of this invention be in
solid particulate form. If they have first been prepared in lumps
or sizable particles they can be reduced to the desired particle
size by conventional grinding methods such as impact, ball, and
tube mills. If the polishing agents are initially prepared in the
form of solid particles having the desired size distribution, a
grinding step is not necessary.
It is preferred that the polishing agents of this invention be
composed of solid particles substantially all of which have a
diameter of less than 50 microns. Larger particles tend to feel
gritty in the mouth and to stick between teeth. The mean diameter
of the particles of the polishing agents is desirably between about
5 microns to about 40 microns and preferably from about 5 microns
to about 20 microns, for optimum performance. Preferably not more
than about 10 weight percent of the particles have a diameter of
less than about 1 micron. Finer particles are relatively
ineffective in cleaning teeth, and therefore the fraction of finer
particles should be limited. By particle is meant aggregates as
well as individual particles. It might be supposed that only
particles with sharp edges and corners would be effective in
removing pellicle film from the teeth. However, it has been
discovered that relatively spherical particles and aggregates of
relatively spherical particles also serve as effective cleaning
agents. (The particle diameters referred to herein were determined
by microscopic measurements using a calibrated eyepiece.)
In the case of fluoride-containing dentifrice compositions the
fluoride ions are usually incorporated in the dentifrice
composition in the form of stannous fluoride which also provides
stannous tin ions (in solution). However, when it is desirable to
control the ratio of stannous ions to fluoride ions, such control
being suggested by the prior art (for example, note U.S. Pat. No.
2,946,725), in order to provide more stannous ions that the
fluoride ions available in stannous fluoride, the stannous tin can
be supplied in the form of a water-soluble, stannous tin salt of a
mineral acid (hereinafter referred to as the other stannous salt).
As examples of such other stannous tin salts, there may be
mentioned, for exemplary purposes only, compounds such as stannous
chloride, stannous sulfate, stannous nitrate, monochlorostannous
fluoride (Sn.sub.2 C1F.sub.3 and SnC1F), fluorostannites -- for
example, KsnF.sub.3, hexafluorozirconate -- for example,
SnZrF.sub.6, and the like.
The other stannous salt content of the dentifrice composition, as
expressed in parts per million of the stannous ions, should be in
the range of from about 2,000 to about 15,000 parts of stannous ion
per million parts of the total weight of such dentifrice
composition. It is generally preferred that the stannous ion be
present, when used in such composition, in the range of from about
6,000 to about 11,000 parts per million stannous tin. Especially
effective dentifrices are usually obtained when the minimum total
stannous tin content is about 6,000 parts per million to about
8,000 parts per million. Experimental evidence indicates that if
the stannous tin content is below the lower limit of 2,000 parts
per million the dentifrice compositions tend to lose some of their
effectiveness in regard to caries prevention. Furthermore, when the
tin content is above about 15,000 parts per million, no further
solubility reduction of the tooth enamel is apparent.
Fluoride ions may be incorporated in the dentifrice compositions of
this invention by the incorporation of any one or mixtures of
water-soluble, innocuous, fluorine-containing organic or inorganic
salts. Many water-soluble inorganic fluoride salts are suitable
sources of fluoride ions, i.e. F.sup.- or complex fluoride ions,
e.g. PO.sub.3 F.sup.- .sup.-.sup.- . Among these salts there may be
mentioned, for exemplary purposes only, InF.sub.3, PbG.sub.2,
FeF.sub.2, LiF, CaF.sub.2, NaF, KF, NH.sub.3 F, PdF.sub.2 and the
like. It should also be understood that the term "fluoride salts,"
as used herein, is also intended to include complex water-soluble
fluoride-containing salts such as fluorophosphates, e.g. Na.sub.2
PO.sub.3 F, fluorosilicates, e.g. Na.sub.2 SiF.sub.6 and H.sub.2
SiF.sub.6, fluorizirconates, e.g. CaZrF.sub.6, Na.sub.2 ZrF.sub.6,
K.sub.2 ZnF.sub.6, fluoroborates, e.g. NaBF.sub.4, and
fluorotitanates. Mixtures of the aforementioned fluoride salts can
also be used herein.
The "fluoride ion," which term includes, for example, both F.sup.-
and PO.sub.3 F.sup.- .sup.-.sup.- or other complex ions, may also
be supplied to the dentifrice composition by means of an organic
fluoride which is soluble in water or at least which dissociates to
give fluoride ions when in contact with water. As examples of
organic fluorides, there may be mentioned the organic
hydrofluorides, i.e. amine fluorides like mono-, di-, and
triethanolamine hydrofluorides, such as those compounds disclosed
in Canadian Pat. 543,066 issued on July 2, 1957, to Philip Zutovern
et al. and which patent is incorporated herein by reference. These
compounds may also be named as the corresponding ethanolammonium
fluorides such as triethanolammonium fluoride. Other useful organic
fluorides and hydrofluorides are disclosed in a publication by H.
R. Muhlemann et al. in Helvetica Odonlotogica, Vol. I, No. 2, page
23, 1957, which publication is also incorporated herein by
reference.
The quantity of the water-soluble fluoride compounds, which may be
used in combination with stannous tin in the dentifrice
compositions of this invention, should be an amount equivalent to
provide at least 25 parts of fluoride ions per million parts of the
total dentifrice composition. It has been found that extremely
large amounts of fluoride ions do not appreciably enhance the
desirable properties of the dentifrice and may, under certain
circumstances, produce toxic effects. Accordingly, it is desirable
that the dentifrices of the present invention contain not more than
a total of about 4,000-5,000 parts of ionized and un-ionized
fluorine per million parts of dentifrice composition and preferably
not more than 3,000 p.p.m. However, a level of from about 1,000 to
about 10,000 p.p.m. fluoride ions can be used, if desired, without
toxic effects. A preferred level of fluoride ions is from about 500
p.p.m. to about 2,000 per million parts of the total dentifrice
composition. (It is to be noted that when the fluoride salt is, for
example, sodium monofluorophosphate, Na.sub.2 PO.sub.3 F, it has
previously been found that it is not necessary to utilize a
stannous tin salt, i.e. to supply Sn.sup.+ .sup.+ , in order to
obtain an effective anticaries dentifrice.)
While the foregoing description has been directed primarily to
various ways of incorporating stannous tin ions and fluoride ions
in a dentifrice composition, it is also possible, as previously
mentioned, to use stannous fluoride per se as the source of
stannous and fluoride ions. Stannous fluoride generally is used in
amounts less than 50,000 parts per million by weight, based on the
total weight of the dentifrice composition. It is preferred that
this salt, i.e. SnF.sub.2, level be less than 25,000 p.p.m. and
between the range of from about 200 p.p.m. and 2,000 p.p.m. by
weight.
Generally the major portion of ingredients (i.e. in excess of 50
percent by weight) of a dentifrice composition comprise the
polishing agent or the polishing agent and fluoride compound.
It is desirable that the pH of the dentifrice composition of this
invention lie between about 5 and about 8, preferably from about 5
to about 7, and more desirably from about 5.5 to about 6.5. When
the pH of the dentifrice composition is above about pH 8, there
results a loss of metal ions, i.e. stannous ions, available for
reaction with enamel and, in addition, certain flavoring
substances, especially esters, deteriorate rapidly. At a pH below
about 4 or 5, there is produced an astringent paste which is
generally objectionable to most people. In addition, the lower pH
also accelerates the hydrolysis of certain of the sudsing agents
normally used in dentifrices thereby producing an unpleasant "fatty
acid taste" and reducing the amount of sudsing obtained.
Furthermore, when the pH values are below 4 or 5, there is a
tendency to cause corrosion of metal tubes in which the paste is
stored and also there is a tendency to hydrolyze other ingredients
in the dentifrice mixture. It should be noted that when referring
to pH herein, the pH values specified are those obtained by
measuring the pH of the supernatant liquid resulting by forming a
slurry of 1 part by weight of dentifrice and 3 parts by weight
distilled water.
In addition to the aforementioned ingredients utilized in the
dentifrice compositions of the present invention, such compositions
may also conventionally contain foaming or sudsing agents although
the use of these agents is not critical in the practice of the
present invention. Any of the commonly used foaming or sudsing
agents can be used if they are reasonably stable, nontoxic and foam
or form suds within the pH range of the dentifrice of this
invention. As examples of suitable sudsing agents, there may be
mentioned water soluble alkyl and alkyl ether sulfates and
sulfonates having alkyl groups of from about light to about 18
carbon atoms, water-soluble salts of sulfonates, monoglycerides of
fatty acids having from about 10 to about 18 carbon atoms,
water-soluble salts of sulfated fatty alcohols having from about 10
to about 18 carbon atoms, salts of fatty acid amides of taurines
such as sodium-N-methyl-N-palmitoyl tauride, salts of fatty acid
esters of isethionic acid, and salts of substantially saturated
aliphatic acyl amides of saturated aliphatic monoaminocarboxylic
acids having from about two to about six carbon atoms and in which
the acyl radical contains from about 12 to about 16 carbon atoms,
such as sodium N-lauroyl sarcoside. It is also to be understood
that mixtures of two or more sudsing agents can be utilized herein.
These sudsing agents are generally used in an amount of from about
0.5 percent to about 5.0 percent by weight, based on the weight of
the dentifrice composition.
In addition to the aforementioned ingredients, it may also be
necessary, in order to obtain the proper consistency in certain
toothpastes, to add various thickening materials. As examples of
such thickening materials there may be mentioned water-soluble
salts of cellulose ethers such as sodium carboxymethylcellulose and
sodium carboxymethyl hydroxyethyl cellulose. Natural gums such as
gum karaya, gum arabic, and gum tragacanth also can be used as
thickneners but may tend to cause undesirable odors or flavors in
some formulations. In addition to the above-mentioned thickeners,
colloidal magnesium aluminum silicate or finely divided silica
(such as silica aerogels or fume silica) can also be used as a part
of the thickening agent for improvement in texture. These
thickening agents are generally used in an amount of from about 0.5
percent to about 5.0 percent by weight, based on the weight of a
toothpaste dentifrice composition.
The dentifrice compositions of the present invention may also
include, in addition to any of the aforementioned ingredients,
suitable humectants, such as glycerine, sorbitol and other
polyhydric alcohols. These humectants are generally used in an
amount of from about 0.5 percent to about 35 percent of the
dentifrice composition.
The dentifrice compositions may also additionally contain small
amounts of flavorings such as oil of wintergreen, oil of
peppermint, oil of spearmint, oil of sassafras, and oil of anise.
Small amounts of sweetening agents such as saccharin, dextrose,
levulose, and sodium cyclamante are also conventionally added to
dentifrices.
In toothpaste formulations, water is generally used as a base and
is present in an amount of from about 5 percent to about 60 percent
by weight, based on the total weight of the composition.
Finally, if one further desires, a suitable coloring agent may be
added to said dentifrice composition in order to enhance its
aesthetic effect.
All of the aforementioned ingredients which are utilized in the
present invention dentifrice compositions may be incorporated
therein in any order, in order to formulate said compositions.
A further understanding of the novel and unique compositions of the
present invention will be obtained from the following specific
examples which are intended to illustrate the invention, but not to
limit the scope thereof, parts and percentages being by weight
unless otherwise specified.
EXAMPLE I
A toothpaste was prepared by first grinding 800 grams of solid
particles of the monocalcium salt of 1-hydroxy, 1-ethylidene
diphosphonic acid as the dihydrate, that is, CaH.sub.2
(PO.sub.3)C(OH)(CH.sub.3)(PO.sub.3).sup.. 2H.sub.2 O, until at
least 90 percent of the particles were of a size within the range
of about 1 to about 20 microns. The resulting material was the
polishing agent. Next a solution was prepared by mixing together
306 grams of glycerine, 306 grams of water and 1 gram of
saccharine, which solution was heated to 90.degree. C. while
thoroughly mixing the ingredients. This solution was then added
with thorough mixing to the aforementioned polishing agent, and to
the resultant mixture was added a solution consisting of (a) 60
milliliters of water, (b) 28 grams of sodium laurylsulfate, (c) 60
grams of glycerine and (d) 10 grams of mint flavoring. The
resulting paste mixture was thoroughly mixed together until a
toothpaste consistency was achieved. This paste which has a pH of
about 5 was a satisfactory cleaning agent for teeth when used in
the customary way with a toothbrush, and had a dentin abrasion
value of about 285.
EXAMPLE II
A toothpaste was prepared using the same ingredients and procedure
described in example I with the exception that a slurry of 11.8
grams of stannous fluoride in 50 milliliters of water was used
instead of the 60 milliliters of water referred to under (a) in
example I. The resulting paste was stored in a closed bottle for 30
days at 20.degree. C., after which a sample was withdrawn from the
bottle and analyzed for percent available fluoride in order to
ascertain the compatibility, as hereinafter defined, of the
polishing agent in the presence of fluoride and stannous tin ions.
The available fluoride and stannous tin is that fluoride and tin
which have not been hydrolyzed or oxidized and which are available
for absorption by the enamel of a tooth surface.
The aforementioned fluoride ion "compatibility" was determined in
the following manner. Approximately 10 grams of the toothpaste were
shaken with 100 milliliters of distilled water for 1 hour at a
setting of 4 (the range is from 1 to 10 with 10 being the fastest)
on an automatic shaker, commercially available under the trade name
Burrell shaker. The resulting slurry was then centrifuged for 15
minutes at the maximum speed in a high-speed centrifuge,
commercially available under the trade name Servell centrifuge. A
25-milliliter portion of the clear supernatant liquid was
transferred to a small bottle containing 4 grams of tricalcium
phosphate. The bottle was capped and placed in the above-described
Burrell shaker and shaken for 20 minutes at a setting of 4. The
resultant tricalcium phosphate sample treated with the slurry made
from the toothpaste formulation was then transferred to a Buchner
funnel, filtered and washed with three 15-milliliter portions of
water and then washed with three 15-milliliter portions of acetone
and then finally dried in air. The sample was then analyzed for
fluorine content by emission spectroscopy. The percent of
compatibility, that is, the amount of fluoride ions remaining after
a period of time when in contact with the aforementioned abrasives
is determined in accordance with the following formula:
As a result of the above-described analytical procedure it was
determined that the toothpaste after 30 day's storage had a
fluoride compatibility of 31.7 percent. By way of contrast a
comparable toothpaste prepared by using calcium pyrophosphate
(Ca.sub.2 P.sub.2 O.sub.7) as the abrasive or polishing agent had a
fluoride compatibility of about 15.9 percent.
It can readily be seen then, from the aforementioned results, that
the calcium salt of alkylene diphosphonic acid not only has a low
dentin abrasion value but is quite compatible with a dentifrice
composition containing fluoride ions in such a composition during
an extended storage period.
EXAMPLE III
The aforementioned example II of the present invention was repeated
with the exception that in place of the slurry of stannous fluoride
dissolved in water, there was substituted a slurry of a mixture of
stannous nitrate and sodium fluoride dissolved in water. Such
mixture was used in an amount to provide the same stannous and
fluoride ion concentrations as obtained in example II. The results
obtained were substantially the same as those results set forth in
example II. Thus, the use of separate and different compounds to
provide stannous and fluoride ions to the dentifrice composition
yields the same abrasive compatibility results as contrasted to the
utilization of stannous fluoride.
EXAMPLE IV
The aforementioned example II of the present invention was again
repeated with the exception that in place of the slurry of stannous
fluoride dissolved in water, there was substituted a mixture of
sodium monofluorophosphate dissolved in water. The amount of such
sodium monofluorophosphate used was sufficient to provide
approximately 2,000 parts per million of fluoride ions, i.e.
PO.sub.3 F.sup.- .sup.-.sup.- . The results obtained were
substantially the same as those results set forth in example II
with reference to the available fluoride in a toothpaste mixture
stored over a period of approximately 30 days. From these results
showing the compatibility of sodium monofluorophosphate with the
calcium salt of alkylene diphosphonic acid, it can readily be seen
that this abrasive material is compatible with a wide variety of
fluoride-containing water-soluble salts.
EXAMPLE V
A toothpowder was prepared by thoroughly mixing together 96 grams
of the polishing agent described in example I together with 1.5
grams of powdered sodium lauryl sulfate, 1.2 grams of oil of
peppermint, 1 gram of sodium citrate and 0.3 gram of saccharine. A
slurry of the resulting toothpowder had a pH of about 5, and a
dentin abrasion value of about 285.
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