GB2201593A - Toothpaste compositions - Google Patents

Abstract

Toothpaste compositions containing a soluble pyrophosphate salt as a anticalculus agent and potassium ions wherein such compositions are formulated to optimize the compatibility of potassium ions with the composition components comprise (a) a sale and effective amount of a soluble pyrophosphate salt or mixture thereof; (b) 5-60% of abrasive; (c) Fluoride ion source to provide 50 - 3500 ppm fluoride ion; (d) 5 - 60% of humectant chosen from sorbitol, glycerine, polyethylene glycols, mineral oil and mixtures thereof; (e) 0.3 - 5% of surfactant comprising alkyl sulphate optionally ethoxylated; and (f) water, the composition being pH 6 - 10 and containing 0.5 - 7% potassium ions. p

Description

ORAL COMPCSITIONS TECHNICAL FIELD The present invention relates to toothpaste compositions which provide an anticalculus benefit.

BACKGROUND OF THE INVENTION Dental calculus, or tartar as it is sometimes called, is a deposit which forms on the surfaces of the teeth at the gingival margin. Supragingival calculus appears principally in the areas near the orifices of the salivary ducts; e.g., on the lingual surfaces of the lower anterior teeth and on the buccal surfaces of the upper first and second molars, and on the distal surfaces of the posterior molars.

Mature calculus consists of an inorganic portion which is largely calcium phosphate arranged in a hydroxyapatite crystal lattice structure similar to bone, enamel and dentine. An organic portion is also present and consists of desquamated epithelial cells, leukocytes, salivary sediment, food debris and various types of microorganisms.

As the mature calculus develops, it becomes visibly white or yellowish in color unless stained or discolored by some extraneous agent. In addition to being unsightly and undesirable from an aesthetic standpoint, the mature calculus deposits are regarded by many as a constant source of mechanical irritation of the gingiva.

A wide variety of chemical and biological agents have been suggested in the art to retard calculus formation or to remove calculus after it is formed. Mechanical removal of this material periodically by the dentist is, of course, routine dental office procedure.

The chemical approach to calculus inhibition generally involves chelation of calcium ion and/or crystal growth inhibition which prevents the calculus from forming and/or breaks down mature calculus by removing calcium.

U.S. Patent 4,515,712, May 7, 1985 to Parran et al. discloses oral compositions containing dialkali metal and mixtures of dialkali metal and tetraalkali metal pyrophosphate salts. The prior art, however, is silent about the compatibility problems associated with the use of potassium ions in pyrophosphate salt systems. Potassium pyrophosphate, having a high degree of solubility in water, is an excellent pyrophosphate source. One big problem associated with potassium ions is the formation of an insoluble potassium alkyl sulfate. Other problems involve the incompatibility of potassium ions with alcohol and alcohol type components of a dentifrice.

It is an object of the present invention to provide compositions which deliver an effective anticalculus benefit.

It is a further object of the present invention to provide an effective anticalculus product utilizing compositions which are formulated to optimize the compatibility of potassium ions with the composition components. The formation of the aforementioned potassium alkyl sulfate precipitate is thereby minimized.

It is a further object of the present invention to provide an anticalculus product which does not inhibit remineralization of the teeth.

It is still a further object of the present invention to provide an effective method for treating calculus.

It is still a further object of the prevent invention to provide compositions which are cosmetically acceptable.

These and other objects will become more clear from the detailed description which follows.

All percentages and ratios used herein are by weight unless otherwise specified.

SUMMARY OF THE INVENTION The present invention embraces an oral composition comprising: a) a safe and effective amount of a soluble pyrophosphate salt; b) from about 58 to about 60% of a suitable toothpaste abrasive; c) an amount of a fluoride ion source sufficient to provide from about 50 ppm to about 3500 ppm fluoride; d) from about 5% to about 60% of a humectant selected from the group consisting of sorbitol, glycerine, polyethylene glycols, mineral oil and mixtures thereof; e) from about 0.396 to about 58 of a surfactant selected from the group consisting of alkyl sulfate surfactants, ethoxylated alkyl sulfate surfactants, and mixtures thereof;; and f) water, wherein said composition has a pH of from about 6 to about 10, is substantially free of polyethylene glycols having 6 or fewer ethoxy groups and short chain monohydric alcohols and has potassium ions present at a level of 0.5% to about 7%.

DETAILED DESCRIPTION OF THE INVENTION The compositions of the present invention comprise soluble pyrophosphate salts and potassium ions, which compositions are more stable than compositions which are not as carefully formulated.

By "safe and effective amount" as used herein, means sufficient compound to reduce calculus while being safe to the hard and soft tissues of the oral cavity.

By the term "comprising", as used herein, is meant that various additional components can be conjointly employed in the compositions of this invention as long as the pyrophosphate performs its intended functions.

Pyrophosphate Salts The pyrophosphate salt used in the present compositions can be any of the alkali metal pyrophosphate salts. Specific salts include the alkali metal tetra alkali metal pyrophosphate, dialkali metal diacid pyrophosphate, trialkali metal monoacid pyrophosphate and mixtures thereof, wherein the alkali metals are preferably sodium or potassium. The salts are useful in both their hydrated and unhydrated forms. The amount of pyrophosphate salt useful in the present composition is any effective amount and is -LI generally enough to provide at least 1 . 5% P207 to the compositions. It is to be appreciated that the level of P207 is that provided to the composition and that other pyrophosphate forms (e.g., HP2O73) may be present when the salt is totally dissolved and a pH established.

The pyrophosphate salts are described in more detail in Kirk & Othmer, Encyclopedia of Chemical Technology, Second Edition, Volume 15, Interscience Publishers (1968), incorporated herein by reference.

The potassium ions present in the compositions described herein may be provided by the pyrophosphate salts and a preferred salt is potassium pyrophosphate because of its excellent solubility. Mixtures of the tetra potassium salt with other pyrophosphate salts are also preferred.

Toothpaste Abrasive The abrasives useful in the dentifrice compositions of the present invention include many different materials. The material selected must be one which has good compatibility with both fluoride ions and polyphosphate ions. In this respect the abrasive must be able to allow for the quantities of fluoride ions and polyphosphate ions indicated herein below. Suitable abrasives include beta-phase calcium pyrophosphate prepared in accordance with the teaching of Schweizer, U.S. Patent 3,112,247, November 26, 1963. The beta-phase calcium pyrophosphate is prepared by heating gamma-phase calcium pyrophosphate to 700-9000C to change at least 50% of the gamma-phase to beta-phase and then immediately cooling. Another class of abrasives for use herein is the particulate thermosetting polymerized resins as described in Cooley et al. in U.S. Patent 3,070,510, December 25, 1962. Suitable resins include, for example, melamines, phenolics, ureas, melamine-ureas, melamine formaldehydes, urea-formaldehydes, melamine-urea-formaldehydes, cross-linked epoxides, and cross-linked polyester. Still other abrasives suitable for use in the dentifrice compositions include alumina and insoluble metaphosphates.

Silica dental abrasives, of various types, can provide the unique benefits of exceptional dental cleaning and polishing performance without unduiy abrading tooth enamel or dentin.

Silica abrasive materials are also exceptionally compatible with sources of soluble fluoride. For these reasons they are preferred for use herein.

The silica abrasive polishing materials useful herein, as well as the other abrasives, generally have an average particle size ranging between about 0.1 to 30 microns, preferably 5 and 15 microns. The silica abrasive can be precipitated silica or silica gels such as the silica xerogels described in Pader et al., U.S.

Patent 3,538,230, issued March 2, 1970 and DiGiulio, U.S. Patent 3,862,307, June 21, 1975, both incorporated herein by reference.

Preferred are the silica xerogels marketed under the tradename "Syloid" by the W. R. Grace s Company, Davison Chemical Division. Preferred precipitated silica materials include those marketed by the J. M. Huber Corporation under the tradename, "Zeodent", particularly the silica carrying the designation "Zeodent 119". These silica abrasives are described in U.S.

Patent 4,340,583, July 29, 1982, incorporated herein by reference.

The abrasive in the toothpaste compositions described herein is present at a level of from about 5% to about 60%, preferably from about 15% to about 25%.

Humectant Sorbitol and glycerine are humectants useful in the present compositions. These materials generally are present at a level of from about 58 to about 20% on a individual basis and from about 5% to about 60% on a collective basis, based on a pure humectant basis. Additionally, polyethylene glycols may be used provided the number of ethoxy groups is greater than six. Mineral oil may also be used particularly mineral oils having a viscosity less than about 100 centipoise when measured at a temperature less than 1000F.

Surfactant Toothpastes generally contain a surfactant to provide sudsing action to the paste when used. A common surfactant is an alkyl sulfate or an ethoxylated alkyl sulfate salt or a mixture thereof. The salts may include, for example, the sodium, potassium or ammonium salt. The alkyl sulfate (e.g. sodium C12 alkyl sulfate) is very good at providing sudsing but presents problems when potassium ions are present due to the formation of an insoluble potassium alkyl sulfate. Even though the sodium salt of the surfactant may be used, when potassium ions are present, they will interchange with the sodium ions to form the potassium salt. The surfactant is generally present at a level of from about 0.3% to about 5%, preferably from about 0.5% to about 2% on a pure surfactant basis.

Fluoride lon Source Another essential component of the compositions herein is a fluoride ion source. The number of such sources is great and includes those disclosed in U.S. Patent 3,535,421, October 20, 1970 to Briner et al., incorporated herein by reference. Typical materials include: stannous fluoride, potassium fluoride, sodium fluoride, cesium fluoride, ammonium fluoride, aluminum fluoride, cupric fluoride, indium fluoride, stannous fluorozirconate, lead fluoride, ferrice fluoride, nickel fluoride, paladium fluoride, silver fluoride, zinc fluoride, zirconium fluoride, hexylamine hydrofluoride, laurylamine hydrofluoride, myristoxyamine, hydrofluoride, diethylaminoethyloctoylamide hydrofluoride, diethanolamineoethyloleylamide hydrofluoride, diethanolamino propyl-N '-octadecenylamine dihydrofluoride, 1 -ethanol-2-hexadecylimidazoline dihydrofluoride, octoylethanolamine hydrofluoride, octyltrimethylammonium fluoride, dodecylethyldimethylammonium fluoride, tetraethylammonium fluoride, dilauryldimethylammonium 8,9 fluoride.A -octadecenylbenzyldimethylammonium fluoride, dioctyldiethylammonium fluoride, cyclohexylcetyldimethylammonium fluoride, furfuryllauryldimethylammonium fluoride, phenoxyethyl cetyldimethylammonium fluoride, N : N'tetramethyl-N :N; -dilauryl- ethylenediammonium difluoride, N-cetylpyridinium fluoride, N'1N-dilauryl-morpholinium fluoride, N-myristyl-N-ethylmorpholinium fluoride, N-(octylaminocarbonylethyl) -N-benzyl- dimethylammonium fluoride, N (-hydroxydodecyl) trimethyl ammonium fluoride, N -phenyl-N-hexadecyidiethyl-ammon ium fluoride, N-cyclohexy I-N-octadecyldimethy lammonium fluoride, N- ( 2-carbocyclohexoxyethyl ) -N-myristyldimethylammonium fluoride, N-(2-carbobenzyloxyethyl ) -N-dodecyldimethylammonium fluoride, N- [2-( N:N '-dimethylaminocarbonyl)-ethyl 1 -N-dodecyldiethylammoni- um fluoride, N-carboxymethyl-N-cicosyldimethylammonium fluoride, betaine hydrofluoride, sarcosine stannous fluoride, alanine stannous fluoride, glycine potassium fluoride, sarcosine potassium fluoride, glycine hydrofluoride, lysine hydrofluoride, sodium monofluoro phosphate and mixtures thereof. Sodium fluoride is the preferred fluoride source.

The amount of the fluoride ion source should be sufficient to provide from about 50 ppm to 3500 ppm, preferably from about 500 ppm to 3000 ppm of fluoride ions.

Water Water is also present in the toothpastes of this invention.

Water employed in the preparation of commercially suitable toothpastes should preferably be deionized and free of organic impurities. Water generally comprises from about 10% to 60%, preferably from about 20% to 408, by weight of the toothpaste compositions herein. These amounts of water include the free water which is added plus that which is introduced with other materials such as with sorbitol.

Potassium lons The potassium ions present in the compositions of this invention can be introduced into the compositions by means of the pyrophosphate salt(s) or other materials such as sweeteners, binders and flavors. The amount of potassium ions is related to the amount of alkyl sulfate or ethoxylated sulfate and is generally in the range of from about 0.5% to about 7%, preferably from about 1% to about 3%.

Optional Components In preparing topthpastes, it is necessary to add some thickening material to provide a desirable consistency. Preferred thickening agents are carboxyvinyl polymers, carrageenan, hydroxyethyl cellulose and water soluble salts of cellulose ethers such as sodium carboxymethyl cellulose and sodium carboxymethyl hydroxyethyl cellulose. Natural gums such as gum karaya, gum arabic, and gum tragacanth can also be used. Colloidal magnesium aluminum silicate or finely divided silica can be used as part of the thickening agent to further improve texture. Thickening agents in an amount from 0.5% to 5.0% by weight of the total composition can be used.

Flavoring agents can also be added to toothpaste compositions. Suitable flavoring agents include oil of wintergreen, oil of peppermint, oil of spearmint, oil of sassafras, and oil of clove.

Sweetening agents which can be used include aspartame, acesulfame, saccharin, dextrose, levulose and sodium cyclamate.

Flavoring and sweetening agents are generally used in toothpastes at levels of from about 0.0058 to about 2% by weight.

As was noted earlier, the compositions of the present invention are substantially free of polyethyleneglycols having fewer than about six ethoxy groups and short chain (e.g., methyl, ethyl, isopropyl) monohydric alcohols. By substantially free is meant less than about 2% of the materials are present.

Method of Manufacture The compositions are made using conventional mixing techniques. A method is described in Example I.

COMPOSITION USE The present invention in its method aspect involves applying to the oral cavity safe and effective amounts of the pyrophosphate salt. Generally an amount of at least about 1.9 grams of the material is effective.

The following examples further describe and demonstrate preferred embodiments within the scope of the present invention.

The examples are given solely for illustration and are not to be construed as limitations of this invention as many variations thereof are possible without department from the spirit and scope thereof.

EXAMPLE I The following is a toothpaste representative of the present invention.

Component Wt. % Sorbitol (70% aqueous solution) 9.297 Double reverse osmosis water 28.129 Sodium fluoride 0.243 Sodium saccharin 0.300 Tetrapotassium pyrophosphate (65% aqueous solution) 4.967 Tetrasodium pyrophosphate 1.834 Sodium acid pyrophosphate 2.680 PEG-12 4.000 Titanium dioxide 0.500 Color 0.050 Flavor 1.000 Silica abrasive 21.000 Sodium alkyl sulfate (27% aqueous solution) 4.000 Gel slurry 22.000 Total 100.000 Gel Slurry Sorbitol (70% aqueous solution) 9.070 Glycerine 12.000 Iota carrageenan 0.770 Carbopol 940S1 0.160 Carbopol 940S is a carboxyvinyl polymer offered by B. F.

Goodrich Company.

The above composition is prepared by placing the main batch of sorbitol, water, sodium fluoride and sodium saccharin in a mix tank which is heated to from about 1000F to about 1100F. The heated mixture is mixed until clear. Sufficient tine to reach clarity is about 10 to 15 minutes.

To the mixture is added the tetrapotassium pyrophosphate solution, the tetrasodium pyrophosphate and the sodium acid pyrophosphate, in that order. This mixture is heated to from about 1300F to about 1400F and mixed for from about 5 to about 10 minutes until clarity is obtained.

The gel slurry is prepared at this time and is held for subsequent use.

After clarity is obtained in the main mix tank, the silica, surfactant, and gel slurry are added with the total mixture being heated to from about 1600F to about 1700F. Minor components (titanium dioxide, color and flavor) are then added and the final mixture mixed for about 15 minutes. The mixture is finally milled, deaerated and packed into dispersion.

EXAMPLE 11 The following is a toothpaste representative of the present invention.

Component Wt. 9s Sorbitol (70% aqueous solution) 2.510 Double reverse osmosis water 34.916 Sodium fluoride 0.243 Sodium saccharin 0.300 Tetrapotassium pyrophosphate (65% aqueous solution) 4.967 Tetrasodium pyrophosphate 1.834 Sodium acid pyrophosphate 2.680 PEG-12 4.000 Titanium dioxide 0.500 Color 0.050 Flavor 1.000 Silica abrasive 21.000 Sodium alkyl sulfate (27% aqueous solution) 4.000 Gel slurry 22.000 Total 100.000 Gel Slurry Sorbitol (70% aqueous solution) 6.070 Glycerine 15.000 lota carrageenan 0.770 Carbopol 940S 0.160 EXAMPLE Ill The following is a toothpaste representative of the present invention.

Component Wt. g6 Mineral oil 3.753 Double reverse osmosis water 33.641 Sodium fluoride 0.243 Sodium saccharin 0.288 Tetrapotassium pyrophosphate (65% aqueous solution) 4.967 Tetrasodium pyrophosphate 1 .834 Sodium acid pyrophosphate 2.680 PEG-12 4.000 Titanium dioxide 0.500 Color 0.050 Flavor 1.044 Silica abrasive 21.000 Sodium alkyl sulfate (27% aqueous solution) 4.000 Gel slurry 22.000 Total 100.000 Gel Slurry Mineral oil 9.070 Glycerine 12.000 lota carrageenan 0.770 Carbopol 940S 0.160 EXAMPLE IV The following is a toothpaste representative of the present invention.

Component Wt. % Sorbitol (70% aqueous solution) 14.500 Double reverse osmosis water 26.959 Sodium fluoride 0.243 Sodium saccharin 0.320 Tetrapotassium pyrophosphate (65% aqueous solution) 8.470 Sodium acid pyrophosphate 2.680 Titanium dioxide 0.500 Color 0.050 Flavor 1.000 Silica abrasive 22.000 Sodium ethoxylated aklyl sulfate (308 aqueous solution) 5.000 Gel slurry 18.278 Total 100.000 Gel Slurry Sorbitol 7.200 Glycerine 10.278 lota carrageenan 0.650 Carbopol 940S 0.150 WHAT IS CLAIMED IS:

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (1)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   Sodium acid pyrophosphate 2.680 Titanium dioxide 0.500 Color 0.050 Flavor 1.000 Silica abrasive 22.000 Sodium ethoxylated aklyl sulfate (308 aqueous solution) 5.000 Gel slurry 18.278 Total 100.000 Gel Slurry Sorbitol 7.200 Glycerine 10.278 lota carrageenan 0.650 Carbopol 940S 0.150 WHAT IS CLAIMED IS:

   1. An oral composition in the form of a toothpaste effective in reducing calculus comprising: a) a safe and effective amount of a soluble pyrophosphate salt or mixture of said salts; b) from about 5% to about 60% of a suitable toothpaste abrasive; c) an amount of a fluoride ion source sufficient to provide from about 50 ppm to about 3500 ppm fluoride; d) from about 5% to about 60% of humectant selected from the group consisting of sorbitol0 glycerine, polyethylene glycols, mineral oil, and mixtures thereof; e) from about 0.3% to about 5% of a surfactant selected from the group consisting of alkyl sulfate surfactants, ethoxylated alkyl sulfate surfactants and mixtures thereof; and f) water, wherein said composition has a pH of from about 6 to about 10, is substantially free of polyethylene glycols having fewer than six ethoxy units and short chain monohydric alcohols and has potassium ions present at a level of from about 0.58 to about 7%.

   2. An oral composition according to Claim 1 wherein the soluble pyrophosphate salt is selected from the group consisting of tetrapotassium pyrophosphate, tetrasodium pyrophosphate, sodium acid pyrophosphate and mixtures thereof.

   3. An oral composition according to Claim 2 wherein the abra sive is selected from the group consisting of beta phase calcium pyrophosphate, silica, thermosetting resins, alumina and insoluble metaphosphates.

   4. An oral composition according to Claim 3 wherein the fluoride ion source is sodium fluoride.

   5. An oral composition according to Claim 4 wherein the humectant is a mixture of sorbitol and glycerine.

   6. An oral composition according to Claim 5 wherein the surfactant is selected from the group consisting of sodium alkyl sulfate, ammonium alkyl sulfate and mixtures thereof.

   7. An oral composition according to Claim 5 wherein the surfactant is selected from the group consisting of sodium ethoxylated alkyl sulfate, ammonium ethoxylated alkyl sulfate and mixtures thereof.

   8. An oral composition according to Claim 6 wherein the pyrophosphate salt is tetrapotassium pyrophosphate.

   9. An oral composition according to Claim 8 wherein the abra sive is a silica abrasive.

   10. An oral composition according to Claim t wherein the soluble pyrophosphate salt is capable of providing at least about -4

   1.5% P207 4 to said composition.