Oral care compositions and methods of using same

Abstract

The present application relates to an oral care composition, and methods of using the same. In particular, the oral care composition comprises an orally acceptable carrier, zinc phosphate, and stannous fluoride.

Description

[0001] This application is a divisional application of a Chinese patent application with an application date of June 22, 2017, application number "201780009622.2", and invention name "Oral Care Composition and Method of Using the Composition". The original application is the Chinese national phase application of international application PCT / US2017 / 038713. Technical Field

[0002] The present disclosure generally relates to an oral care composition comprising zinc phosphate and stannous fluoride, and methods of using the composition. Background Art

[0003] Dental erosion involves demineralization and damage to tooth structure due to acid attack from non-bacterial sources. Erosion is initially found in the enamel and, if not inhibited, may progress to the underlying dentin. Dental erosion may be caused or exacerbated by acidic foods and beverages, exposure to chlorinated swimming pool water, and stomach acid reflux.

[0004] Tooth enamel is a negatively charged surface that naturally tends to attract positively charged ions such as hydrogen and calcium ions, while repelling negatively charged ions such as fluoride ions. Depending on the relative pH of the surrounding saliva, tooth enamel will lose or gain positively charged ions, such as calcium ions. Typically saliva has a pH between 7.2 and 7.4. When the pH decreases, the fluid medium surrounding the teeth becomes unsaturated with respect to the tooth mineral phase and the teeth dissolve, releasing calcium and phosphate ions. This damages the tooth enamel and forms a porous, spongy, rough surface. If the saliva remains acidic for a long time, remineralization may not occur and the teeth will continue to lose minerals, causing the teeth to weaken and eventually lose structure.

[0005] Heavy metal ions, such as zinc, are resistant to acid corrosion. Zinc ranks higher than hydrogen in the electrochemical series, so when zinc enters the solution, it forms the divalent cation Zn 2+ When exposed to acidic solutions, zinc metal reacts to release hydrogen gas. Zinc has also been shown to have antimicrobial properties in dental plaque and caries studies.

[0006] Soluble zinc salts such as zinc citrate have been used in dentifrice compositions, but have several disadvantages. Zinc ions in solution impart an unpleasant astringent mouthfeel, making it difficult to obtain a formulation that provides effective levels of zinc and also has acceptable organoleptic properties. In addition, free zinc ions may react with fluoride ions to form zinc fluoride, which is insoluble, thereby reducing the availability of both zinc and fluoride. Finally, zinc ions will react with anionic surfactants such as sodium lauryl sulfate, interfering with foaming and cleaning.

[0007] Although zinc phosphate (Zn3(PO4)2) is soluble in acidic or alkaline solutions, such as solutions of mineral acids, acetic acid, ammonia or alkali metal hydroxides, it is insoluble in water. See, e.g., Merck Index, 13th edition, (2001) page 1812, Monograph No. 10205. In part because zinc phosphate is a material that would be considered generally inert in the art, it is commonly used in dental cements, such as for the cementation of inlays, crowns, bridges and orthodontic appliances, which are intended to last in the mouth for many years. Zinc phosphate dental cements are typically prepared by mixing zinc oxide and magnesium oxide powders with a liquid consisting primarily of phosphoric acid, water and a buffer, whereby the cement containing the zinc phosphate is formed in situ by reaction with the phosphoric acid.

[0008] Stannous fluoride is well known in clinical dentistry for its therapeutic benefits for more than four decades. However, until recently, its popularity was limited by its instability in aqueous solution. The instability of stannous fluoride in water is mainly due to the presence of stannous ions (Sn 2+ ). Tin readily hydrolyzes at pH above 4, leading to precipitation in solution and consequently loss of therapeutic properties.

[0009] Methods to overcome the stability problem of stannous fluoride include forming a gel in anhydrous or water-poor formulations by dissolving the stannous fluoride in anhydrous substances such as glycerol or by using chelating agents. However, these solutions can be relatively expensive and cumbersome.

[0010] Improved compositions for treating and reducing tooth enamel erosion are desirable. Also desirable are new antimicrobial compositions that are stable in water and relatively easy to manufacture. Summary of the invention

[0011] One embodiment of the present disclosure is directed to an oral care composition comprising zinc phosphate and stannous fluoride. In some embodiments, the zinc phosphate is added to the dentifrice as a preformed salt.

[0012] Other areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter.It should be understood that although the detailed description and specific examples indicate preferred embodiments of the present disclosure, these detailed description and specific examples are intended for illustrative purposes only and are not intended to limit the scope of the present disclosure. DETAILED DESCRIPTION

[0013] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses.

[0014] As used throughout, ranges are used as shorthand for describing each value within a range. Any value within a range can be selected as the endpoint of the range. In addition, all references cited herein are hereby incorporated by reference in their entirety. If a definition in the present disclosure conflicts with a definition in the cited reference, the present disclosure shall prevail.

[0015] Unless otherwise specified, all percentages and amounts expressed herein and elsewhere in this specification should be understood to refer to percentages by weight. The amounts given are based on the effective weight of the material.

[0016] One embodiment of the present disclosure relates to an oral care composition for intermittent use, such as daily use in the form of a dentifrice, gel, lozenge, mint, chewing gum or other suitable oral care formulation. The oral care composition comprises zinc phosphate, stannous fluoride and water. In some embodiments, the zinc phosphate is added to the oral care composition as a preformed salt. As used herein, the term "preformed salt" when used with respect to zinc phosphate means that the zinc phosphate is not formed in situ in the oral care composition, such as by the reaction of phosphoric acid and another zinc salt.

[0017] In one aspect, the present disclosure thus provides an oral care composition (Composition 1) comprising an orally acceptable carrier, zinc phosphate and stannous fluoride. In other embodiments of this aspect, the present disclosure provides:

[0018] 1.1 Composition 1, wherein the zinc phosphate is a preformed salt of zinc phosphate.

[0019] 1.2 Composition 1 or 1.1 wherein the zinc phosphate is present in an amount sufficient to dissociate the stannous fluoride to provide a therapeutically effective amount of stannous ions in aqueous solution.

[0020] 1.3 Any of the preceding compositions, wherein the amount of zinc phosphate is from 0.05% to 5% by weight, e.g., from 0.1% to 4% by weight, or from 0.5% to 3% by weight, or from 0.5% to 2% by weight, or from 0.8% to 1.5% by weight, or from 0.9% to 1.1% by weight, or about 1% by weight, or from 2% to 3% by weight, or about 2% by weight, or about 2.25% by weight, or about 2.5% by weight, relative to the weight of the oral care composition.

[0021] 1.4 Any of the preceding compositions, wherein the amount of stannous fluoride is from 0.05% to 11% by weight, e.g., from 0.05% to 7% by weight, or from 0.1% to 5% by weight, or from 0.2% to 3% by weight, or from 0.2% to 2% by weight, or from 0.2% to 1% by weight, or from 0.2% to 0.8% by weight, or from 0.4% to 0.6% by weight, or from 0.4% to 0.5% by weight, or about 0.45% by weight (e.g., 0.454% by weight), relative to the weight of the oral care composition.

[0022] 1.5 Any of the preceding compositions, wherein the amount of water is about 12 wt % or more, such as 15 wt % to 85 wt %, or 20 wt % to 75 wt %, or 20 wt % to 40 wt %, or 20 wt % to 30 wt %, or 25 wt % to 50 wt %, or 30 wt % to 40 wt %, such as about 35 wt %, or about 25 wt %, or about 20 wt %, relative to the weight of the oral care composition.

[0023] 1.6 Any of the preceding compositions, wherein the oral care composition further comprises an abrasive, such as silica abrasives, calcium abrasives, and other abrasives disclosed herein.

[0024] 1.7 Any of the preceding compositions, further comprising one or more wetting agents and / or one or more surfactants as described herein.

[0025] 1.8 Any of the preceding compositions further comprising an effective amount of one or more alkali metal phosphates, such as orthophosphates, pyrophosphates, tripolyphosphates, tetraphosphates or higher polyphosphates.

[0026] 1.9 Composition 1.8, wherein the alkali metal phosphate comprises tetrasodium pyrophosphate or tetrapotassium pyrophosphate, for example in an amount of 0.5% to 5% by weight of the composition, for example 1% to 3%, or 1% to 2%, or about 2%, or about 2% to 4%, or about 3% to 4%, or about 4% by weight of the composition.

[0027] 1.10 Composition 1.8 or 1.9, wherein the alkali metal phosphate comprises sodium tripolyphosphate or potassium tripolyphosphate, for example in an amount of 0.5% to 6% by weight of the composition, for example 1% to 4% by weight, or 2% to 3% by weight, or about 3% by weight.

[0028] 1.11 Any of the preceding compositions further comprising a whitening agent.

[0029] 1.12 Any of the preceding compositions, further comprising, in addition to zinc phosphate, one or more sources of zinc ions, such as a zinc salt selected from zinc citrate, zinc oxide, zinc lactate, zinc pyrophosphate, zinc sulfate or zinc chloride.

[0030] 1.13 Any of the preceding compositions wherein the oral care composition is a dentifrice.

[0031] 1.14 Any of the foregoing compositions, wherein the composition comprises:

[0032] 0.5 to 3 wt % zinc phosphate;

[0033] 0.05 to 11 wt % stannous fluoride;

[0034] 1 to 8 wt % of an alkali metal phosphate selected from disodium hydrogen phosphate, dipotassium hydrogen phosphate, dicalcium phosphate dihydrate, tetrasodium pyrophosphate, tetrapotassium pyrophosphate, calcium pyrophosphate, sodium tripolyphosphate, and mixtures of any two or more of these, relative to the weight of the oral care composition; and

[0035] Silica abrasive.

[0036] 1.15 Any of the preceding compositions wherein the composition is substantially free of halogenated diphenyl ethers.

[0037] 1.16 Any of the preceding compositions, wherein the oral care composition is a dentifrice (eg, toothpaste or oral gel), powder (eg, tooth powder), cream, stick or gum (eg, chewing gum), for example wherein the oral care composition is a gel.

[0038] 1.17 Any of the preceding compositions wherein the oral care composition is a lozenge or a mint.

[0039] 1.18 Any of the preceding compositions wherein the oral care composition is chewing gum.

[0040] 1.19 Any of the preceding compositions wherein the pH of the composition is from 6 to 9, such as from 6.5 to 8, or from 3 to 7, or from 4 to 7, or from 5 to 7, or from 5 to 6.

[0041] 1.20 Any of the preceding compositions, wherein the composition is a single-phase composition (eg, not a two-phase composition).

[0042] 1.21 Any of the preceding compositions, wherein the composition does not comprise one or more of zinc oxide, zinc citrate, or zinc lactate.

[0043] 1.22 Any of the preceding compositions wherein the zinc phosphate is the sole source of zinc ions.

[0044] 1.23 Any of the preceding compositions, wherein the composition is substantially free of hexametaphosphate (eg, sodium hexametaphosphate).

[0045] Any amount of zinc phosphate effective to prevent enamel erosion and / or provide any other benefit described herein may be employed. Examples of suitable amounts of zinc phosphate may be 0.05% to 5% by weight, such as 0.1% to 4% by weight, or 0.5% to 3% by weight, or 0.5% to 2% by weight, or 0.8% to 1.5% by weight, or 0.9% to 1.1% by weight, or about 1%, relative to the weight of the oral care composition.

[0046] Although zinc phosphate is considered to be insoluble in water (e.g., poorly water soluble), when placed in a formulation, for example, at an acidic or alkaline pH, zinc phosphate can be sufficiently dissolved at the time of use to provide an effective concentration of zinc ions to tooth enamel, thereby protecting it from erosion, reducing bacterial colonization and biofilm development, and providing enhanced shine to teeth. It has also been found that zinc phosphate in a formulation with a second phosphate source enhances phosphate deposition. As explained in WO2014 / 088573, the disclosure of which is incorporated herein by reference in its entirety, it is completely unexpected that zinc phosphate is substantially inert under conditions in the oral cavity, as demonstrated by its widespread use in dental cements, given its poor solubility and the art-recognized view. At the same time, formulations containing zinc phosphate do not exhibit the bad taste and mouthfeel, poor fluoride delivery, and poor foaming and cleaning associated with conventional zinc-based oral care products using more soluble zinc salts.

[0047] A certain amount of, preferably an effective amount of, stannous fluoride is used in combination with the zinc phosphate in the composition of the present disclosure. For example, stannous fluoride can be used to effectively provide antimicrobial benefits such as anti-caries protection and / or anti-gingivitis protection and / or the amount of the anti-erosion benefits for protecting tooth enamel. The example of the suitable amount of stannous fluoride is in the range of 0.05% by weight to 11% by weight relative to the gross weight of the dentifrice composition, such as 0.05 to 7% by weight, or 0.1% to 5% by weight, or 0.2 to 3% by weight, or 0.2 to 2% by weight, or 0.2 to 1% by weight, or 0.2 to 0.8% by weight, or 0.4 to 0.6% by weight, or 0.4 to 0.5% by weight, or about 0.45% by weight (for example, 0.454%). The preparation can include the stannous level provided by stannous fluoride, and the stannous level range is, for example, 3000ppm to 15,000ppm (mass fraction) of stannous ions in the total composition. In an embodiment, the soluble stannous content may be in the range of 0.1 wt % to 0.5 wt % or more, such as 0.15 wt % to 0.32 wt %, based on the total weight of the composition.

[0048] The combination of zinc ions and stannous ions provides one or more of the following benefits: improved antimicrobial benefit compared to zinc ions alone; improved control of dental plaque and / or gingivitis; improved protection from enamel erosion.

[0049] In compositions containing a large amount of water, zinc phosphate acts as a stabilizer for stannous fluoride, so that stannous fluoride is retained in an aqueous solution. As discussed above, stannous fluoride is generally considered to be unstable in water due to the hydrolysis and oxidation loss of stannous ions in the typical pH range used in oral care compositions. Therefore, stannous fluoride is generally used in compositions without water or low water, or is used together with a chelating agent. A cumbersome procedure is used to provide a stable solution, wherein the tendency of stannous ions to be oxidized or hydrolyzed is suppressed. The applicant has unexpectedly found that zinc phosphate and stannous fluoride can be combined in a single-phase formulation using standard mixing methods and a typical pH range to form a stable aqueous oral care composition. Zinc phosphate remains substantially insoluble in the composition. However, stannous fluoride has been shown to remain dissolved and stable for a long time (such as 3 months or longer) at 40°C in a solution containing a relatively large amount of water. Under typical storage conditions, it is expected that stannous fluoride remains sufficiently stable to provide, for example, a required shelf life of 1 to 2 years or longer.

[0050] The water of any desired amount can be used in the composition of the present disclosure.The example of the suitable amount of water is 12 wt % or more, such as in the range of 15 wt % to 98 wt % or 99 wt %.For example, the amount of water can be 15% to 85% or 20% to 75% or 25% to 50% or 30% to 40%, for example about 35% by weight of the composition.These amounts will change according to the type of oral care composition.In an embodiment where the composition is a dentifrice (such as toothpaste), the amount of water can be in the range of, for example, 15 wt % to 60 wt %, such as 25 wt % to 50 wt % or 25 wt % to 40 wt % relative to the gross weight of the dentifrice composition.

[0051] The amount of water in the composition as shown in the above range includes free water added separately plus the amount introduced with other ingredients. The water used to prepare the oral composition of the present disclosure can be deionized (sometimes referred to as demineralized water) and / or free of organic impurities. In addition to directly added water, sources of water include ingredients that are usually added in aqueous solution, such as sorbitol (usually provided as a 70% w / w aqueous solution).

[0052] The composition can optionally include other ingredients suitable for oral care compositions.Except zinc phosphate, the example of this type of composition includes an active agent, such as a fluoride source and / or a phosphate source.The composition can be prepared in a suitable dentifrice base material that, for example, comprises an abrasive such as a silica abrasive, a surfactant, a foaming agent, a vitamin, a polymer, an enzyme, a humectant, a thickener, another antimicrobial agent, a preservative, a flavoring agent, a coloring agent and / or a combination thereof.The example of a suitable dentifrice base material is known in the art.Or, the composition can be formulated into a gel (for example, used in a dental tray), a chewing gum, a lozenge or a mint.The example of the suitable other ingredients that can be used in the composition of the present disclosure will be discussed in more detail below.

[0053] Active Agent The compositions of the present disclosure may include various other active agents that protect and enhance the strength and integrity of tooth enamel and tooth structure and / or reduce bacteria and associated caries and / or gum disease or provide other desired benefits. The effective concentration of the active ingredient used herein will depend on the specific agent and delivery system used. The concentration will also depend on the exact salt or polymer selected. For example, in the case of providing the active agent in salt form, the counterion will affect the weight of the salt so that if the counterion is heavier, more salt will be required by weight to provide the same concentration of active ions in the final product.

[0054] The compositions of the present disclosure may include 0.1 wt % to 1 wt % antimicrobial agent, such as about 0.3 wt % antimicrobial agent.Any suitable antimicrobial active may be employed.

[0055] Fluoride ion sourceOral care compositions may also include one or more fluoride ion sources, such as soluble fluoride salts. A variety of fluoride ion-producing materials may be used as soluble fluoride sources in the compositions of the present invention. Examples of suitable fluoride ion-producing materials are found in U.S. Pat. No. 3,535,421 to Briner et al., U.S. Pat. No. 4,885,155 to Parran, Jr. et al., and U.S. Pat. No. 3,678,154 to Widder et al., the disclosures of each of which are hereby incorporated herein by reference in their entirety. Representative fluoride ion sources include, but are not limited to, sodium fluoride, potassium fluoride, sodium monofluorophosphate, sodium fluorosilicate, ammonium fluorosilicate, amine fluoride, ammonium fluoride, and combinations thereof. In certain embodiments, the fluoride ion source comprises sodium fluoride, sodium monofluorophosphate, and mixtures thereof. In certain embodiments, the oral care composition of the present disclosure may contain stannous fluoride and any additional source of a fluoride ion source or an agent providing fluorine, the amount of which is sufficient to provide a total of 25ppm to 25,000ppm (mass fraction), typically at least 500ppm, such as 500ppm to 2000ppm, such as 1000ppm to 1600ppm, such as about 1450ppm of fluoride ions. The appropriate content of fluoride will depend on the specific application. Toothpaste for general consumer use will typically have 1000ppm to about 1500ppm, with children's toothpaste being slightly lower. Dentifrice or coating for professional use may have up to about 5,000ppm or even about 25,000ppm of fluoride. In addition, a fluoride ion source may be added to the composition of the present disclosure at the following levels by weight of the composition: about 0.01% by weight to 10% by weight in one embodiment, or about 0.03% by weight to 5% by weight, and 0.1% by weight to 1% by weight in another embodiment. As discussed above, the weight of fluoride salt to provide an appropriate level of fluoride ion will vary based on the weight of the counter ion in the salt.

[0056] Abrasive The compositions of the present disclosure may include an abrasive. Examples of suitable abrasives include silica abrasives, such as standard cleaning silica, high cleaning silica, or any other suitable abrasive silica. Other examples of abrasives that may be used in addition to or in place of silica abrasives include, for example, calcium phosphate abrasives, such as tricalcium phosphate (Ca3(PO4)2), hydroxyapatite (Ca 10 (PO4)6(OH)2) or dicalcium phosphate dihydrate (CaHPO4·2H2O, sometimes also referred to herein as DiCal) or calcium pyrophosphate; calcium carbonate abrasive; or abrasives such as sodium metaphosphate, potassium metaphosphate, aluminum silicate, calcined alumina, bentonite or other siliceous materials, or combinations thereof.

[0057] Silica abrasive polishing materials and other abrasives suitable for use herein typically have an average particle size in a range between 0.1 microns and 30 microns, such as between 5 microns and 15 microns. The silica abrasive may be derived from precipitated silica or silica gel, such as the silica xerogels described in U.S. Pat. No. 3,538,230 to Pader et al. and U.S. Pat. No. 3,862,307 to Digiulio, the disclosures of which are incorporated herein by reference in their entirety. Specific silica xerogels are available from WR Grace & Co. Davison Chemical Division under the trade name Precipitated silica materials include those sold by JM Huber Corp. under the trade name Those sold include silicas with the designations Zeodent 115 and 119. These silica abrasives are described in U.S. Pat. No. 4,340,583 to Wason, the disclosure of which is incorporated herein by reference in its entirety. In certain embodiments, abrasive materials useful in the practice of oral care compositions according to the present disclosure include silica gels and precipitated amorphous silicas having an oil absorption value of less than 100cc / 100g silica, such as 45cc / 100g silica to 70cc / 100g. The oil absorption value is measured using ASTA Rub-Out Method D281. In certain embodiments, the silica is a colloidal particle having an average particle size of 3 to 12 microns and 5 to 10 microns. Examples of low oil absorption silica abrasives useful in the practice of the present invention are sold under the trade name Sylodent Sylodent 650 is sold by Davison Chemical Division of WR Grace & Co., Baltimore, Md. 21203. is an example of a low oil absorption silica abrasive useful in the practice of the present invention, which is a silica hydrogel composed of particles of colloidal silica having a water content of 29% by weight, an average diameter of 7 to 10 microns, and an oil absorption of less than 70 cc / 100 g silica.

[0058] Any suitable amount of silica abrasive may be employed. Examples of suitable amounts include 10 wt% or more dry weight of silica particles, based on the total weight of the composition, such as 15 wt% to 30 wt% or 15 wt% to 25 wt%.

[0059] Foaming agent:The oral care composition of the present disclosure may also include an agent that increases the amount of foam produced when brushing the oral cavity. Illustrative examples of agents that increase the amount of foam include, but are not limited to, polyoxyethylene and certain polymers, including but not limited to alginate polymers. Polyoxyethylene can increase the amount of foam produced by the oral care composition of the present disclosure and the density of the foam. Polyoxyethylene is also commonly referred to as polyethylene glycol ("PEG") or polyethylene oxide. Polyoxyethylene suitable for compositions of the present disclosure may have a molecular weight of 200,000 to 7,000,000. In one embodiment, the molecular weight may be 600,000 to 2,000,000, and in another embodiment 800,000 to 1,000,000. is a trade name for high molecular weight polyoxyethylenes produced by Union Carbide. The foaming agent (e.g., polyoxyethylene) may be present in an amount of 0.1% to 50%, in one embodiment 0.5% to 20%, and in another embodiment 1% to 10%, or 2% to 5% by weight of the oral care composition of the present disclosure.

[0060] Surfactants : The compositions useful in the compositions of the present disclosure may contain anionic surfactants, such as:

[0061] i. water-soluble salts of monosulfated monoglycerides of higher fatty acids, such as sodium salts of monosulfated monoglycerides of hydrogenated coconut oil fatty acids, such as sodium N-methyl N-cocoyl taurate, sodium cocoyl monoglyceride sulfate,

[0062] ii. Higher alkyl sulfates, such as sodium lauryl sulfate,

[0063] iii. Higher alkyl ether sulfates, for example, formula CH3(CH2) m CH2(OCH2CH2) n Higher alkyl ether sulfates of OSO3X, wherein m is 6-16, such as 10, n is 1-6, such as 2, 3 or 4, and X is Na or K, such as sodium laureth sulfate (CH3(CH2) 10 CH2(OCH2CH2)2OSO3Na),

[0064] iv. higher alkyl aryl sulfonates, such as sodium lauryl benzene sulfonate (sodium lauryl benzene sulfonate),

[0065] v. Higher alkyl sulfoacetates, such as sodium lauryl sulfoacetate (sodium lauryl sulfoacetate), higher fatty acid esters of 1,2-dihydroxypropane sulfonic acid, sulfocolaurate (potassium N-2-ethyllaurate sulfoacetamide) and sodium lauryl sarcosinate.

[0066] "Higher alkyl" means, for example, C 6-30 Alkyl. In certain embodiments, anionic surfactants useful herein include water-soluble salts of alkyl sulfates having 10 to 18 carbon atoms in the alkyl group and water-soluble salts of sulfonated monoglycerides of fatty acids having 10 to 18 carbon atoms. Sodium lauryl sulfate, sodium lauroyl sarcosinate, and sodium coconut monoglyceride sulfonate are examples of this type of anionic surfactants. In a specific embodiment, the anionic surfactant is selected from sodium lauryl sulfate and sodium lauryl ether sulfate. In a specific embodiment, the composition of the present disclosure includes sodium lauryl sulfate. The anionic surfactant can be effective (e.g., greater than 0.01% by weight of the formulation), but not in an amount that will stimulate the oral tissue (e.g., less than 10%), and the optimal concentration depends on the specific formulation and the specific surfactant. In one embodiment, the anionic surfactant is present in a toothpaste at 0.3% by weight to 4.5% by weight, such as about 1.5% by weight. The composition of the present disclosure may optionally contain a mixture of surfactants, for example, including anionic surfactants and other surfactants that may be anionic, cationic, zwitterionic or nonionic. Generally, suitable surfactants are those that are reasonably stable over a wide pH range. Surfactants are described, for example, in U.S. Pat. Nos. 3,959,458 to Agricola et al.; 3,937,807 to Haefele; and 4,051,234 to Gieske et al., the disclosures of which are incorporated herein by reference in their entirety.

[0067] Surfactants or mixtures of compatible surfactants in addition to anionic surfactants may be present in the compositions of the present disclosure at 0.1% to 5.0%, in another embodiment 0.3% to 3.0%, and in another embodiment 0.5% to 2.0% by weight of the total composition. These ranges do not include the amount of anionic surfactants.

[0068] In one embodiment, the composition of the present disclosure comprises a zwitterionic surfactant, e.g., a betaine surfactant, such as cocamidopropyl betaine, e.g., in an amount of 0.1 wt % to 4.5 wt %, e.g., 0.5 wt % to 2 wt % cocamidopropyl betaine.

[0069] Tartar Control Agents:In various embodiments of the present disclosure, the composition comprises an anticalculus agent (tartar control agent). Suitable anticalculus agents include, but are not limited to, phosphates and polyphosphates (e.g., pyrophosphates and tripolyphosphates), polyaminopropanesulfonic acid (AMPS), hexametaphosphates, zinc citrate trihydrate, polypeptides, polyolefin sulfonates, polyolefin phosphates, and diphosphonates. Thus, the compositions of the present disclosure may comprise phosphates in addition to zinc phosphate. In specific embodiments, these salts are alkali metal phosphates, such as salts of alkali metal hydroxides or alkaline earth metal hydroxides, such as sodium, potassium, or calcium salts. As used herein, "phosphate" encompasses orally acceptable monophosphates and polyphosphates, such as P 1-6 Phosphate, for example monomeric phosphate, such as monobasic phosphate, dibasic phosphate or tribasic phosphate; With dipolyphosphate, such as pyrophosphate; With polyphosphate, such as triphosphate, tetraphosphate, hexaphosphate and hexametaphosphate (for example, sodium hexametaphosphate). In a specific example, the selected phosphate is selected from alkali metal dibasic phosphate and alkali metal pyrophosphate, for example, selected from disodium hydrogen phosphate, dipotassium hydrogen phosphate, dicalcium phosphate dihydrate, calcium pyrophosphate, tetrasodium pyrophosphate, tetrapotassium pyrophosphate, sodium tripolyphosphate and any two or more of these mixtures. In a specific embodiment, for example, the composition can include 0.5% by weight to 5% by weight, for example 1% by weight to 3% by weight or 1% by weight to 2% by weight or about 2% by weight of the amount of tetrasodium pyrophosphate. In another embodiment, the composition may include a mixture of tetrasodium pyrophosphate (TSPP) and sodium tripolyphosphate (STPP), for example, TSPP in a proportion of 0.5% to 5%, for example 1% to 2%, and STPP in a proportion of 0.5% to 6%, for example 1% to 4%, or 2% to 3%, by weight of the composition. Such phosphates are provided in an amount effective to reduce erosion of tooth enamel to help clean teeth and / or reduce plaque accumulation on teeth, for example 0.2% to 20%, for example 1% to 15%.

[0070] Flavoring :The oral care composition of the present disclosure may also include flavoring agents. Flavoring agents used in the practice of the present disclosure include, but are not limited to, essential oils and various flavoring aldehydes, esters, alcohols, and the like. Examples of essential oils include oils of spearmint, peppermint, holly, sassafras, cloves, sage, eucalyptus, marjoram, cinnamon, lemon, lime, grapefruit, and orange. Chemicals such as menthol, carvone, and anethole are also suitable. Certain embodiments employ peppermint oil and spearmint oil. Flavoring agents may be incorporated into the oral composition at a concentration of 0.1% to 5% by weight, such as 0.5% to 1.5% by weight.

[0071] polymer:Oral care compositions of the present disclosure may also include additional polymers to adjust the viscosity of the formulation or enhance the solubility of other ingredients. Such additional polymers include polyethylene glycol, polysaccharides (e.g., cellulose derivatives, such as hydroxymethylcellulose, microcrystalline cellulose or polysaccharide gums, such as xanthan gum or carrageenan). Acidic polymers (e.g., polyacrylate gels) may be provided in the form of their free acids or partially or completely neutralized water-soluble alkali metals (e.g., potassium and sodium) or ammonium salts. In one embodiment, oral care compositions may include PVP. PVP generally refers to a polymer containing vinyl pyrrolidone (also referred to as N-vinyl pyrrolidone, N-vinyl-2-pyrrolidone and N-vinyl-2-pyrrolidone) as a monomer unit. The monomer unit is composed of a polar imide group, four non-polar methylene groups and a non-polar methane group.

[0072] Silica thickeners that form polymer structures or gels in aqueous media can be present. Note that these silica thickeners are physically and functionally different from the particulate silica abrasives that are also present in the composition, because the silica thickeners are very finely dispersed and provide little or no grinding action. Other thickeners are water-soluble salts of carboxyvinyl polymers, carrageenan, hydroxyethyl cellulose and cellulose ethers, such as sodium carboxymethyl cellulose and sodium carboxymethyl hydroxyethyl cellulose. Natural gums such as karaya gum, gum arabic and tragacanth gum can also be incorporated. Colloidal magnesium aluminum silicate can also be used as a component of thickening compositions to further improve the texture of the composition. In certain embodiments, a thickener of an amount of 0.5 % by weight to about 5.0 % by weight is used by the weight of the total composition.

[0073] The compositions of the present disclosure may include anionic polymers, for example, in an amount of 0.05 to 5%. Examples of such agents commonly known for use in dentifrices are disclosed in U.S. Pat. Nos. 5,188,821 and 5,192,531, the disclosures of which are incorporated herein by reference in their entirety; and include synthetic anionic polymeric polycarbonates, such as 1:4 to 4:1 copolymers of maleic anhydride or maleic acid with another polymerizable ethylenically unsaturated monomer, preferably methyl vinyl ether / maleic anhydride with a molecular weight (MW) of 30,000 to 1,000,000, for example 300,000 to 800,000. These copolymers are available, for example, as Gantrez, for example, AN 139 (MW 500,000), AN 119 (MW 250,000) and preferred S-97 pharmaceutical grade (MW 700,000) available from ISP Technologies, Inc., Bound Brook, NJ08805. When present, the reinforcing agent is present in an amount of 0.05% to 3% by weight. Other functional polymers include those such as 1:1 copolymers of maleic anhydride with ethyl acrylate, hydroxyethyl methacrylate, N-vinyl-2-pyrrolidone or ethylene, the latter being available, for example, as Monsanto EMA No. 1103, MW 10,000 and EMA Grade 61; and 1:1 copolymers of acrylic acid with methyl methacrylate or hydroxyethyl methacrylate, methyl acrylate or ethyl acrylate, isobutyl vinyl ether or N-vinyl-2-pyrrolidone. Generally, suitable are polymerized olefinic or ethylenically unsaturated carboxylic acids containing an activated carbon-carbon olefinic double bond and at least one carboxyl group, i.e., acids containing an olefinic double bond that readily functions in polymerization because it is present in the monomer molecule in the alpha-beta position relative to the carboxyl group or as part of a terminal methylene group. Such acids are exemplified by acrylic acid, methacrylic acid, ethacrylic acid, α-chloroacrylic acid, crotonic acid, β-acryloyloxypropionic acid, sorbic acid, α-chlorosorbic acid, cinnamic acid, β-styryl acrylic acid, mucofuric acid, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, α-phenylacrylic acid, 2-phenylmethylacrylic acid, 2-cyclohexylacrylic acid, angelic acid, umbelliferous acid, fumaric acid, maleic acid and anhydride. Other different olefinic monomers that can be copolymerized with such carboxyl-containing monomers include vinyl acetate, vinyl chloride, dimethyl maleate, etc. The copolymer contains sufficient carboxyl salt groups for water solubility. Another class of polymerizing agents includes compositions containing homopolymers of substituted acrylamides and / or homopolymers of unsaturated sulfonic acids and salts thereof, particularly wherein the polymer is an unsaturated sulfonic acid based on acrylamidoalkylsulfonic acid such as 2-acrylamido-2-methylpropanesulfonic acid having a molecular weight of 1,000 to 2,000,000.Another class of useful polymerizing agents includes polyamino acids containing proportions of anionic surface active amino acids, such as aspartic acid, glutamic acid and phosphoserine, for example, as described in US Pat. No. 4,866,161 issued to Sikes et al., which is also incorporated herein by reference in its entirety.

[0074] Wetting agent In some embodiments of the oral composition, it is also desirable to mix a wetting agent to prevent the composition from hardening after being exposed to air. Some wetting agents can also impart desirable sweetness or flavor to the dentifrice composition. Suitable wetting agents include edible polyhydroxy alcohols, such as mixtures of glycerine, sorbitol, xylitol, propylene glycol and other polyols and these wetting agents. In one embodiment of the present disclosure, main wetting agents are one of glycerine, sorbitol or their combination. Wetting agents can be greater than 15 wt %, such as 15 wt %% to 55 wt %, or 20 wt % to 50 wt %, or 20 wt % to 40 wt %, or about 20 wt %, or about 30 wt %, or about 40 wt % levels based on the gross weight of the composition.

[0075] Other optional ingredients In addition to the above components, embodiments of the present disclosure may also contain a variety of optional oral care ingredients, some of which are described below. Optional ingredients include, for example, but are not limited to, adhesives, foaming agents, flavoring agents, sweeteners such as sodium saccharin, additional anti-plaque agents, abrasives, aesthetics such as TiO2-coated mica or other colorants such as dyes and / or pigments.

[0076] In one embodiment, the composition of the present disclosure may have any pH suitable for an oral care product. An example of a suitable pH range is 6 to 9, such as 6.5 to 8.

[0077] In one embodiment, the oral care compositions of the present disclosure are substantially free of or free of any sodium hexametaphosphate, such as used in the compositions of U.S. Pat. No. 3,095,356, the disclosure of which is incorporated herein by reference in its entirety. In one embodiment, the oral care compositions of the present disclosure are substantially free of or free of any halogenated diphenyl ethers, such as cited in U.S. Patent Application Publication No. 2013 / 0216485, the disclosure of which is incorporated herein by reference in its entirety. In one embodiment, the oral care compositions of the present disclosure are substantially free of or free of any TRPV1 activators and / or vanillin, such as used in the compositions taught in CA 2760445, the disclosure of which is incorporated herein by reference in its entirety. In one embodiment, the oral care composition of the present disclosure is substantially free of or free of any high intensity sweetener selected from the group consisting of sucralose (sucralose), acesulfame potassium, neohesperidin DC, thaumatin, glycyrrhizin, mogroside IV, mogroside V, cyclocarya paliurus I, N-[N-[3-(3-hydroxy-4-methoxyphenyl)propyl]-L-α-aspartyl]-L-phenylalanine 1-methyl ester, N-[N-[3-(3-hydroxy-4-methoxyphenyl)-3-methyl-butyl]-L-α-aspartyl]-L-phenylalanine 1-methyl ester, N-[N-[3-(3-methoxy-4-hydroxyphenyl)-propyl]-L-α-aspartyl]-L-phenylalanine 1-methyl ester, and mixtures thereof. In one embodiment, the compositions of the present disclosure are substantially free or free of 10% of any high intensity sweeteners having a sucrose equivalent of 500-600, as disclosed in U.S. Patent Application Publication No. 2012 / 0082630, the disclosure of which is incorporated herein by reference in its entirety. "Substantially free" means that the composition has no more than 0.01% by weight of these compounds.

[0078] In one embodiment, the compositions of the present disclosure are substantially free of or free of any complexing agent used to increase the solubility of zinc phosphate and / or to maintain stannous fluoride in solution. Examples of known complexing agents that may be excluded from the compositions of the present disclosure include the chelating agents taught in U.S. Patent Application 2007 / 0025928, the disclosure of which is incorporated herein by reference in its entirety. Such chelating agents include mineral surfactants, including mineral surfactants that are polymers and / or polyelectrolytes and are selected from phosphorylated polymers, wherein if the phosphorylated polymer is a polyphosphate, the average chain length of the polyphosphate is 3.5 or more, such as 4 or more; polyphosphonates; polycarboxylates; carboxyl substituted polymers; copolymers of phosphate or phosphonate containing monomers or polymers with ethylenically unsaturated monomers, amino acids, proteins, polypeptides, polysaccharides, poly(acrylates), poly(acrylamides), poly(methacrylates), poly(ethylacrylates), poly(hydroxyalkyl methacrylates), poly(vinyl alcohols), poly(maleic anhydrides), poly(maleic esters), polyamides, poly(vinylamines), poly(ethylene glycols), poly(propylene glycols), poly(vinyl acetates), poly(vinylbenzyl chlorides); and mixtures thereof. Other known complexing agents that may be excluded from the compositions of the present disclosure include those taught in CA 2634758, the disclosure of which is incorporated herein by reference in its entirety. Examples include polyphosphorylated inositol compounds such as phytic acid, inositol penta(dihydrogen phosphate); inositol tetra(dihydrogen phosphate), inositol tri(dihydrogen phosphate) and alkali metal salts, alkaline earth metal salts or ammonium salts of any of the above inositol compounds. Phytic acid is also known as inositol 1,2,3,4,5,6-hexa(dihydrogen phosphate) or inositol hexaphosphate.

[0079] The present patent application also discloses methods for increasing zinc levels in tooth enamel and treating, reducing or controlling the occurrence of tooth enamel erosion using the compositions described herein. The method comprises applying any composition as described herein to the teeth, for example, by brushing or otherwise applying the composition to the oral cavity of a subject in need. The composition can be applied regularly, for example, once or more times a day. In various embodiments, applying the compositions of the present disclosure to a patient can provide one or more of the following benefits: (i) reducing tooth hypersensitivity, (ii) reducing plaque accumulation, (iii) reducing or inhibiting demineralization and promoting remineralization of teeth, (iv) inhibiting microbial biofilm formation in the oral cavity, (v) reducing or inhibiting gingivitis, (vi) promoting the healing of herpes or cuts in the mouth, (vii) reducing the level of acid-producing bacteria, (viii) increasing the relative level of non-caries and / or non-plaque-forming bacteria, (ix) ) reduce or inhibit the formation of caries, (x) reduce, repair or inhibit pre-caries lesions of tooth enamel, for example, as detected by quantitative light-induced fluorescence (QLF) or electrical caries measurement (ECM), (xi) treat, alleviate or reduce dry mouth, (xii) clean teeth and oral cavity, (xiii) reduce erosion, (xiv) whiten teeth; (xv) reduce tartar accumulation, and / or (xvi) promote systemic health, including cardiovascular health, for example, by reducing the potential for systemic infection via oral tissue. The present disclosure further provides compositions for use in any of the above methods. Additional embodiments provide methods wherein at least one tooth is remineralized after administration of a composition as described herein.

[0080] The compositions according to the present invention can be prepared by methods and procedures known to those skilled in the art.

[0081] The application also provides a method for preparing any one of the compositions disclosed herein. The method comprises combining zinc phosphate and stannous fluoride in water to form an aqueous zinc phosphate mixture having a water concentration of 12% or more and a pH in the range of 6 to 9 (such as 6.5 to 8). In some embodiments, zinc phosphate is added to the dentifrice composition as a preformed salt and is substantially kept insoluble in the aqueous mixture. The amount of water used in the mixture can be any amount listed herein for the compositions disclosed herein. Any standard mixing technique can be used to combine ingredients and form a stable composition without the need for additional complexing agents to solubilize stannous fluoride, such as any of the complexing agents or chelating agents disclosed above, or using anhydrous mixing techniques such as dissolving stannous fluoride in anhydrous substances such as glycerol.

[0082] Example

[0083] Example 1 - Dentifrice Formulation

[0084] A test dentifrice containing 1% zinc phosphate and 0.454% stannous fluoride was prepared according to the following formulation in Table 1. Ingredients are listed by weight of the composition.

[0085] Table 1

[0086]

[0087] Example 2 - Stability Data

[0088] Three separate dentifrice formulation samples were prepared similar to the formulations shown in Table 1 (above). The three samples were maintained at three different temperatures: room temperature (approximately 25°C), approximately 40°C, and approximately 49°C for a period of three months. The initial fluoride concentration of each sample was measured at the beginning of the study, and then the fluoride concentration was measured periodically after each month of the study. The results showed that in the presence of zinc phosphate, the fluoride concentration remained sufficiently stable at all three temperatures for a period of three months.

[0089] The data show that by simply combining stannous fluoride and zinc phosphate, a stable formulation can be obtained that provides good antimicrobial benefit without employing techniques commonly used to stabilize stannous fluoride compositions in water.

[0090] Example 3

[0091] Example 3 dentifrice was prepared by adding 0.454 wt% of stannous fluoride to a commercially available toothpaste. As a first control sample, a commercially available toothpaste without stannous fluoride was used. Both the Example 3 toothpaste and the first control sample had a zinc phosphate concentration of 1 wt%. Another commercially available fluoride toothpaste containing 1100 ppm (mass fraction) of fluoride and 1 wt% of zinc citrate was used as a second control sample.

[0092] An in vitro method was used to determine the enamel protection activity of the formulation prototype of Example 3. Enamel substrates (N=6 / 8 / group) were prepared by embedding bovine incisors in a methacrylate-based resin and polishing them continuously with 600 and 1200 grit carbide papers. When polishing the enamel to a mirror finish, care was taken not to penetrate the dentin layer. Before testing, all enamel substrates were pre-etched with 5% citric acid for 30 seconds. Half of the side of each substrate was covered with acid-resistant tape to protect it as a control surface. The model for evaluating the product alternated a 1-minute product treatment period with a 2-minute acid exposure period according to the daily order of T-–C-–C-–C-–C-–T (T=product treatment, C=acid challenge). The acid challenge was performed with a 1% citric acid aqueous solution (unbuffered) adjusted to pH=3.8 by NaOH. All enamel substrates were kept in a sterile artificial saliva solution at 37°C without being treated or challenged. The protocol was run for a total of five days, at the end of which microhardness analysis was used to quantify the amount of enamel loss on both protected and exposed surfaces due to erosion on each enamel substrate. The percent change in hardness was calculated. In the untreated case, where deionized water was used instead of the test dentifrice, the percent change in hardness was very high, approximately 80%, with slight variations between experiments depending on the specific substrate.

[0093] The dentifrice of Example 3 and two control samples were tested using the above procedure. The Example 3 formulation, which contained both zinc phosphate and stannous fluoride, was effective against demineralization in this in vitro pH cycling model designed to study the protective effects of treatment against early enamel dissolution, with the mean hardness reduction after repeated acid challenges being only about 89.4 g. f mm -2 This is greater than the 83.32 g observed for the first control sample using zinc phosphate without stannous fluoride. f mm -2 The average hardness of the second control sample was reduced, but still significantly better than the result of the second control sample, which obtained about 98.5g f mm -2 The average hardness of the samples was reduced. Here, the hardness was determined by the Knoop hardness HK test. Therefore, the enamel protection activity of the zinc phosphate and stannous fluoride preparation of Example 3 is considered to be excellent.

[0094] Example 4

[0095] Demineralization / remineralization studies were conducted on bovine teeth for two commercial comparative compositions (Comparative Examples I and II) and an exemplary composition of the present invention (Example 4). The formulations of Comparative Example I and Example 4 are provided in Table 2 below. Comparative Example II is a commercial sodium fluoride toothpaste that does not contain zinc or stannous agents.

[0096] Table 2

[0097]

[0098]

[0099] Bovine teeth were soaked in hot saliva overnight to form a pellicle. The teeth were then treated twice daily for ten (10) days with a 1:2 toothpaste:water slurry and then subjected to an acid challenge of 1% citric acid solution for two minutes.

[0100] As shown by the data set forth in Table 3 (below), only the exemplary compositions of the present disclosure demonstrated the ability to actually remineralize tooth enamel, while the comparative examples failed to provide the same benefit.

[0101] Table 3

[0102] Composition % Mineral Loss Example 4 (-)4.07 Comparative Example I 53.12 Comparative Example 71.29

[0103] Example 5

[0104] A 13-week stability study was performed using two arms, one at room temperature and one at 40°C. Formulation A-1 is a dentifrice containing 0.454% stannous fluoride, 1% zinc phosphate, 1.2% citrate buffer, and 4% TSPP. Formulation B contains 0.454% stannous fluoride, 1% zinc oxide, 1.2% citrate buffer, and 4% TSPP. The results are shown in Table 4 below.

[0105] Table 4

[0106]

[0107] The results show that, although the use of zinc oxide produces fluoride stability comparable to that of zinc phosphate, the soluble tin level and soluble zinc level are significantly reduced at the beginning and during the study when zinc oxide is used instead of zinc phosphate. This demonstrates that zinc phosphate has the ability to stabilize stannous ions against oxidative degradation, whereas zinc oxide does not have this ability. Without being bound by theory, it is believed that zinc oxide can interact unfavorably with stannous fluoride when dissolved, causing the stannous ions to be converted into stannous hydroxide, thereby precipitating out. In contrast, zinc phosphate is able to keep zinc and stannous in a bioavailable soluble form.

[0108] Example 6

[0109] An additional stability study was performed in which recoverable soluble tin was compared between a formulation according to the present invention (Formulation A-2) and two commercial competitors (Comparative Examples B and C). The study was performed at room temperature for 13 weeks. Formulation A-2 contained 0.454% stannous fluoride, 1% zinc phosphate, 1.2% citrate buffer, and 2% TSPP (Formulation A-2 was substantially the same as Formulation A-1 except that it contained 2% TSPP instead of 4% TSPP). Comparative Composition B was a low moisture composition comprising 0.454% stannous fluoride, about 2.5% zinc lactate, and about 10% water. Comparative Composition C was a high moisture composition comprising 0.454% stannous fluoride, 0.27% stannous chloride, 0.5% zinc citrate, and about 43% water. The results shown in Table 5 below demonstrate that, while existing low moisture stannous fluoride compositions can achieve stannous ion stability, high moisture compositions cannot. In fact, the commercial formulation containing more than twice the total tin salt content produced only half of the recoverable soluble tin at the end of the study.

[0110] Table 5

[0111]

[0112] Example 7

[0113] Tin can exist in two oxidation states, Sn(II) (stannous) and Sn(IV) (tin). Oxidants including atmospheric oxygen can oxidize Sn(II) to Sn(IV). Soluble Sn(II) can be rapidly quantified by titration with an inorganic oxidant, iodine, for example according to the method of Howe, P. and Watts, P., Tin and inorganic tin compounds, (World Health Organization, 2005). Formulation A-2 as described above and comparative formulations B and C were tested for soluble tin using this method. The results are shown in Table 6 below. These results further demonstrate that the compositions according to the present invention unexpectedly stabilize tin in high moisture compositions.

[0114] Table 6

[0115] Tin(II) (wt%) Preparation A-2 0.25 Comparative Example B (Low Moisture) 0.13 Comparative Example C (High Moisture) 0.16

[0116] Example 8

[0117] The antibacterial efficacy of preparation A-2 was compared with various commercial competitor preparations using the planktonic bacterial ATP luminescence assay described in Example 3. Preparation A-2 is a dentifrice containing 0.454% stannous fluoride, 1% zinc phosphate, 1.2% citrate buffer and 2% TSPP. Comparative composition C is a high moisture composition comprising 0.454% stannous fluoride, 0.27% stannous chloride, 0.5% zinc citrate and about 43% water. Comparative composition D is a commercially stable stannous dentifrice containing about 0.45% stannous fluoride in a substantially anhydrous (zero water) base. The results are shown in Table 7 below. The sample was diluted 1:8 in a mixture of saliva and PBS. The positive control of saliva alone and the saliva / PBS mixture for sample dilution was measured. The results show that preparation A-2 is significantly more effective in killing bacteria than any commercial competitor.

[0118] Table 7

[0119] Luminescence(cps) Saliva (control) 168398 Saliva / PBS (control) 109810 Preparation A-2 4954 Comparative Example C (High Moisture) 65192 Comparative Example D (Anhydrous) 11612

[0120] While the invention has been described with reference to embodiments, it will be appreciated by those skilled in the art that various modifications and changes may be made therein without departing from the scope of the invention as defined by the appended claims.

[0121] The present disclosure relates to the following embodiments:

[0122] 1. An oral care composition comprising:

[0123] an orally acceptable carrier;

[0124] Zinc phosphate; and

[0125] Stannous fluoride.

[0126] 2. The oral care composition of embodiment 1, wherein the zinc phosphate is a preformed salt of zinc phosphate.

[0127] 3. The oral care composition according to any one of the preceding embodiments, wherein zinc phosphate is present in an amount sufficient to dissociate the stannous fluoride to provide a therapeutically effective amount of stannous ions in aqueous solution.

[0128] 4. The oral care composition according to any one of the preceding embodiments, wherein the amount of zinc phosphate is from 0.05 wt % to 5 wt % relative to the weight of the oral care composition.

[0129] 5. The oral care composition according to any one of the preceding embodiments, wherein the amount of stannous fluoride is 0.05 wt % to 5 wt % relative to the weight of the oral care composition.

[0130] 6. The oral care composition according to any one of the preceding embodiments, wherein the amount of water is about 12 wt % or more relative to the weight of the oral care composition.

[0131] 7. The oral care composition according to any one of the preceding embodiments, wherein the oral care composition further comprises an abrasive.

[0132] 8. The oral care composition according to any one of the preceding embodiments, further comprising one or more humectants and / or one or more surfactants.

[0133] 9. The oral care composition according to any one of the preceding embodiments, further comprising an effective amount of one or more alkali metal phosphates.

[0134] 10. The oral care composition according to any one of the preceding embodiments, further comprising a whitening agent.

[0135] 11. The oral care composition according to any one of the preceding embodiments, further comprising one or more zinc ion sources other than zinc phosphate.

[0136] 12. The oral care composition according to any one of the preceding embodiments, wherein the oral care composition is a dentifrice, powder, cream, bar or gum.

[0137] 13. An oral care composition according to any one of the preceding embodiments, comprising:

[0138] 0.5 to 3 wt % zinc phosphate;

[0139] 0.05 to 11 wt % stannous fluoride;

[0140] 1 to 8 wt % of an alkali metal phosphate selected from disodium hydrogen phosphate, dipotassium hydrogen phosphate, dicalcium phosphate dihydrate, tetrasodium pyrophosphate, tetrapotassium pyrophosphate, calcium pyrophosphate, sodium tripolyphosphate, and mixtures of any two or more of these, relative to the weight of the oral care composition; and

[0141] Silica abrasive.

[0142] 14. The oral care composition of any one of the preceding embodiments, wherein the oral care composition is a gel.

[0143] 15. The oral care composition according to any one of the preceding embodiments, wherein the pH of the composition is less than 7.

[0144] 16. A method of treating or reducing tooth enamel erosion, the method comprising applying the composition according to any one of the preceding embodiments to the oral cavity of a subject in need thereof.

[0145] 17. The method of embodiment 16, wherein at least one tooth is remineralized following administration of the composition.

Claims

1. An oral care composition comprising: an orally acceptable carrier comprising 12% by weight or more water; 0.5 to 3 wt % zinc phosphate; 0.4 to 0.6 wt % stannous fluoride; 1 to 8 weight percent of an alkali metal phosphate selected from pyrophosphate, tripolyphosphate, tetraphosphate, and mixtures of two or more thereof; and a citrate buffer comprising citric acid and sodium citrate; Silica abrasive; and All weight percentages are relative to the total weight of the oral care composition.

2. The oral care composition of claim 1, wherein the zinc phosphate is a preformed salt of zinc phosphate.

3. The oral care composition of claim 1, wherein zinc phosphate is present in an amount sufficient to dissociate the stannous fluoride to provide a therapeutically effective amount of stannous ions in aqueous solution.

4. The oral care composition of claim 1, wherein the alkali metal phosphate is selected from tetrasodium pyrophosphate, tetrapotassium pyrophosphate, calcium pyrophosphate, sodium tripolyphosphate, and mixtures of any two or more of these.

5. The oral care composition of claim 1, wherein the oral care composition is free of hexametaphosphate.

6. The oral care composition of claim 1, wherein the oral care composition is free of zinc oxide, zinc citrate, and zinc lactate.

7. The oral care composition of claim 1, wherein the zinc phosphate is the sole source of zinc ions.

8. The oral care composition of claim 1, further comprising polyethylene glycol present in an amount of 1 wt% to 10 wt%.

9. An oral care composition according to claim 8, wherein the amount of polyethylene glycol is from 1 wt% to 5 wt%.

10. The oral care composition of claim 8, wherein the polyethylene glycol has a molecular weight of 200,000 to 7,000,000.

11. The oral care composition of claim 1, wherein the oral care composition further comprises an abrasive.

12. The oral care composition of claim 11, wherein the abrasive comprises a silica abrasive.

13. The oral care composition of claim 1, further comprising one or more humectants and / or one or more surfactants.

14. The oral care composition of claim 1, further comprising a whitening agent.

15. The oral care composition of claim 1, wherein the oral care composition is a dentifrice, powder, cream, bar, or gum.

16. The oral care composition of claim 1, wherein the oral care composition is a gel.

17. The oral care composition of claim 1, wherein the pH of the composition is less than 7.

18. An oral care composition according to any one of claims 1 to 17 further comprising an anionic polymer selected from methyl vinyl ether / maleic anhydride polymers.

19. The oral care composition of claim 18, wherein the methyl vinyl ether / maleic anhydride polymer has a molecular weight (MW) of 30,000 to 1,000,000.

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