Oral care composition

Abstract

An oral care composition comprising: a) from 20 to 90wt% of the total composition of one or more organic polyols having 3 or more hydroxyl groups in the molecule; b) calcium silicate; c) a sodium phosphate salt; d) mono calcium phosphate e) xanthan gum f) carrageenan.

Description

[0001] ORAL CARE COMPOSITION

[0002] Technical Field of the Invention

[0003] The present invention relates to oral care compositions such as toothpastes, powders, gums, mouthwashes and the like. In particular the present invention relates to an oral care compositions, particularly toothpastes that are effective in mitigating the effects of gastric acid erosion on tooth enamel.

[0004] Background of the Invention

[0005] Gastric acid reflux can lead to chemical erosion of dental enamel, as a result the teeth can appear yellow due to increased dentin visibility and sensitivity problems can arise due to increased exposure of the dentin tubules.

[0006] WO20131616 relates to a method of preventing dental erosion by combinations of a basic amino acid and one or more sources of zinc.

[0007] However there remains the need to provide improved methods of using oral care compositions to protect tooth enamel from the effects of intrinsic stomach acid erosion.

[0008] Description of the Invention

[0009] The present invention relates to an oral care composition comprising: a) from 20 to 90wt% of the total composition of one or more organic polyols having 3 or more hydroxyl groups in the molecule b) calcium silicate c) a potassium phosphate salt d) mono calcium phosphate e) xanthan gum; and f) carrageenan

[0010] In a second aspect the invention relates to an oral care composition as described above for use in a method to mitigate erosion of tooth enamel by gastric acid. Detailed Description of the Invention

[0011] Except in the examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and / or use may optionally be understood as modified by the word “about’.

[0012] All amounts are by weight of the composition, unless otherwise specified.

[0013] It should be noted that in specifying any ranges of values, any upper value can be associated with any particular lower value.

[0014] Where a feature is disclosed with respect to a particular aspect of the invention (for example a composition of the invention), such disclosure is also to be considered to apply to any other aspect of the invention (for example a method of the invention) mutatis mutandis.

[0015] Any ingredients mentioned in this application that are natural or naturally derived have been sourced from Europe.

[0016] The composition of the invention is used to preferably used to clean the surfaces of the oral cavity and is known as an oral care composition.

[0017] Accordingly, preferred product forms for compositions of the invention are those which are suitable for brushing and / or rinsing the surfaces of the oral cavity.

[0018] The composition of the invention is most preferably in the form of a dentifrice. The term "dentifrice" denotes an oral composition which is used to clean the surfaces of the oral cavity. Such a composition is not intentionally swallowed for purposes of systemic administration of therapeutic agents, but is applied to the oral cavity, used to treat the oral cavity and then expectorated. Typically such a composition is used in conjunction with a cleaning implement such as a toothbrush, usually by applying it to the bristles of the toothbrush and then brushing the accessible surfaces of the oral cavity.

[0019] Preferably the dentifrice / toothpaste is in the form of an extrudable semi-solid such as a cream, paste or gel (or mixture thereof). Toothpastes are particularly preferred. Compositions according to the thein invention comprise mono calcium phosphate. Preferably the monocalcium phosphate is present at levels from 0.1 to 10 wt% of the total composition, more preferably 1 to 6 wt%.

[0020] The compositions of the invention comprise from 20 to 90 wt% of the total composition of one or more organic polyols having 3 or more hydroxyl groups in the molecule. Preferably the organic polyol is glycerol.

[0021] The compositions of the invention include agents for the remineralisation of teeth. The term “remineralisation” in the context of the present invention means the in-situ generation of hydroxyapatite on teeth.

[0022] Compositions according to the invention comprise a suitable agent for the remineralisation of teeth this a mixture of a calcium silicate and a sodium phosphate salt which, when delivered to the teeth results in the in situ generation of hydroxyapatite on teeth.

[0023] The amount of remineralising calcium source(s) (e.g. calcium silicate) in the composition of the invention typically ranges from 1 to 30%, preferably from 5 to 20% by total weight remineralising calcium source based on the total weight of the oral care composition.

[0024] Illustrative examples of the types of phosphate that may be used in this context (hereinafter termed “remineralising phosphate sources”) include, for example, monosodium dihydrogen phosphate, disodium hydrogen phosphate, sodium pyrophosphate, tetrasodium pyrophosphate, sodium tripolyphosphate, sodium hexametaphosphate, potassium dihydrogenphosphate, trisodium phosphate, tripotassium phosphate and mixtures thereof. Preferably the remineralising phosphate source is a mixture of trisodium phosphate and sodium dihydrogen phosphate.

[0025] The amount of remineralising phosphate source(s) (e.g. trisodium phosphate and sodium dihydrogen phosphate) in the composition of this invention typically ranges from 2 to 15%, preferably from 4 to 10% by total weight re-mineralising phosphate source based on the total weight of the oral care composition.

[0026] Compositions according to the invention further comprise xanthan gum and carrageenan. It is particularly preferred that carrageenan is either iota or kappa carrageenan, a mixture of the two being particularly preferred. It is preferred if the level of xanthan gum is from 0.1 to 0.9wt% of the total composition.

[0027] It is also preferred if the level of carrageenan is from is from 0.1 to 0.9wt% of the total composition. Preferably the weight ratio of xanthan gum to carrageenan is from 1 :2 to 2: 1.

[0028] Preferably the composition comprises from 0.2 to 5wt% of the total composition of one or more surfactants, such as anionic, nonionic, cationic and zwitterionic or amphoteric surfactants. A preferred surfactant is a taurate, in particular sodium methyl cocoyl taurate.

[0029] A composition according to the invention (such as a dentifrice / toothpaste) will generally contain further ingredients to enhance performance and / or consumer acceptability, in addition to the ingredients specified above.

[0030] Compositions according to the invention, particularly toothpastes, preferably comprise particulate abrasive materials such as silicas, aluminas, calcium carbonates, dicalciumphosphates, calcium pyrophosphates, hydroxyapatites, trimetaphosphates, insoluble hexametaphosphates and so on, including agglomerated particulate abrasive materials, usually in amounts between 3 and 60% by weight of the oral care composition.

[0031] Preferably the composition, particularly a toothpaste, comprises a silica based abrasive. The preferred abrasive silicas used in the present invention is a silica with a low refractive index. It may be used as the sole abrasive silica, or in conjunction with a low level of other abrasive silicas, e.g. those according to EP 236070. The low refractive index silicas, used as abrasives in the present invention are preferably silicas with an apparent refractive index (R.l.) in the range of 1.41 - 1 .47, preferably 1.435 - 1.445, preferably having a weight mean particle size of between 5 and 15 mm, a BET (nitrogen) surface area of between 10 and 100 m2 / g and an oil absorption of about 70 - 150 cm3 / 100 g, but abrasive silicas with a lower apparent refractive index may also be used. Typical examples of suitable low refractive index abrasive silicas (e.g. having an R.l. of between 1.435 and 1.445) are Tixosil 63 and 73 ex Rhone Poulenc; Sident 10 ex Degussa; Zeodent 113 ex Zeofinn; Zeodent 124 ex Evonik, Sorbosil AC 77 ex PQ Corporation (having an R.l. of approximately 1 .440). The amount of these silicas in the composition generally ranges from 5-60% by weight, usually 5- 20% by weight.

[0032] The composition, particularly if a toothpaste preferably comprises an inorganic or a natural or synthetic thickener or gelling agent in proportions of about 0.10 to about 15% by weight depending on the material chosen. These proportions of thickeners in the dentifrice compositions of the present invention form an extrudable, shape-retaining product which can be squeezed from a tube onto a toothbrush and will not fall between the bristles of the brush but rather, will substantially maintain its shape thereon. Suitable thickeners or gelling agents useful in the practice of the present invention include inorganic thickening silicas such as amorphous silicas available from Evonik under the trade designation Zeodent 165, Irish moss, iota-carrageenan, gum tragacanth, and polyvinylpyrrolidone.

[0033] Compositions according to the invention preferably comprise a polymeric deposition aid. Preferably the composition comprises acid anhydride polymers, particularly preferred are co-polymers of maleic anhydride with methyl vinylether, in which the anhydride moiety may be in a partially or folly hydrolysed or alcoholysed form. Preferred copolymers include Gantrez(R) polymers such as: Gantrez S-95: molecular weight 216,000; free acid;

[0034] Gantrez S-96: molecular weight 700,000; free acid;

[0035] Gantrez S-97: molecular weight 1 ,500,000; free acid; and

[0036] Gantrez MS-955: molecular weight 1,060,000; calcium / sodium salt.

[0037] Particularly preferred co-polymers of maleic acid and methyl vinylether have a molecular weight of 1 ,000,000 or greater and an especially preferred material is Gantrez S-97.

[0038] Compositions according to the invention may comprise a tooth whitening agent. The whitening agent preferably comprises a green and / or a blue pigment. In the context of the present invention a pigment is generally understood to be a shade / material which is insoluble in the relevant medium, at the relevant temperature. This is in contrast to dyes which are soluble. In the context of this invention, the "relevant medium" is human saliva, the liquid medium in which the composition is used, at the temperature of the oral cavity during brushing of the teeth, i.e. up to 37 Degrees C. As a reasonable approximation, the relevant medium may be considered to be water and the relevant temperature to be 25 Degrees C.

[0039] Preferably the blue pigment is Pigment Blue 15, more preferably Pigment Blue 15:1, 15:2, 15:3, 15:4, 15:5 or 15:6, most preferably 15:1. A preferred pigment is blue pigment is Phthalocyanine Blue Pigment, Cl No. 74160, blue covarine.

[0040] The preferred Green pigment is Phthalocyanine Green, preferably Phthalocyanine Green CI-74260.

[0041] Preferably the total level of pigment in the composition is from 0.01 wt% to 3 wt%, more preferably from 0.02 to 2 wt%. If the composition is a toothpaste it may be a dual phase paste, with the whitening pigments present in one phase.

[0042] Compositions according to the invention may comprise water-soluble or sparingly water-soluble sources of metal salts Preferred are zinc ions such as zinc chloride, zinc acetate, zinc gluconate, zinc sulphate, zinc fluoride, zinc citrate, zinc lactate, zinc oxide, zinc monoglycerolate, zinc tartrate, zinc pyrophosphate and zinc maleate; also preferred are stannous ions such as stannous fluoride and stannous chloride.

[0043] Compositions according to the invention may comprise oral care enzyme systems such as hydrogen peroxide producing enzyme systems (e.g. the oxidoreductase enzyme glucose oxidase), amyloglucosidase, dextranase and / or mutanase, (optionally in the presence of zinc ion providing compounds and / or 8- hydroxyquinoline derivatives), lactoperoxidase, lactoferrin, lysozyme and mixtures thereof.

[0044] Compositions of the invention may comprise fluoride sources such as sodium fluoride, stannous fluoride, sodium monofluorophosphate, zinc ammonium fluoride, tin ammonium fluoride, calcium fluoride, cobalt ammonium fluoride and mixtures thereof.

[0045] Mixtures of any of the above described materials may also be used.

[0046] The composition according to the invention will comprise further ingredients which are common in the art, such as: antimicrobial agents, e.g. chlorhexidine, sanguinarine extract, metronidazole, quaternary ammonium compounds, such as cetylpyridinium chloride; bis-guanides, such as chlorhexidine digluconate, hexetidine, octenidine, alexidine; and halogenated bisphenolic compounds, such as 2,2' methylenebis-(4-chloro-6-bromophenol); anti-inflammatory agents such as ibuprofen, flurbiprofen, aspirin, indomethacin etc.; anti-caries agents such as sodium- and stannous fluoride, aminefluorides, sodium monofluorophosphate, sodium trimeta phosphate and casein; plaque buffers such as urea, calcium lactate, calcium glycerophosphate and strontium polyacrylates; vitamins such as Vitamins A, C and E; plant extracts; plant-derivable antioxidants such as flavonoid, catechin, polyphenol, and tannin compounds and mixtures thereof; desensitising agents, e.g. potassium citrate, potassium chloride, potassium tartrate, potassium bicarbonate, potassium oxalate, potassium nitrate and strontium salts; anti-calculus agents, e.g. alkali-metal pyrophosphates, hypophosphite-containing polymers, organic phosphonates and phosphocitrates etc.; biomolecules, e.g. bacteriocins, antibodies, enzymes, etc.; flavours, e.g. peppermint and spearmint oils; proteinaceous materials such as collagen; preservatives; opacifying agents; hyaluronic acid; amino acids such as arginine; colouring agents; pH-adjusting agents; sweetening agents; pharmaceutically acceptable carriers, e.g. starch, sucrose, water or water / alcohol systems etc.;

[0047] Humectants such as glycerol, sorbitol, propyleneglycol, xylitol, lactitol etc.; binders and thickeners such as sodium carboxymethyl-cellulose, hydroxyethyl cellulose (Natrosol®), xanthan gum, gum arabic etc. as well as synthetic polymers such as polyacrylates and carboxyvinyl polymers such as Carbopol®; polymeric compounds which can enhance the delivery of active ingredients such as antimicrobial agents can also be included; buffers and salts to buffer the pH and ionic strength of the oral care composition; and other optional ingredients that may be included are e.g. bleaching agents such as peroxy compounds e.g. potassium peroxydiphosphate, effervescing systems such as sodium bicarbonate / citric acid systems, colour change systems, and so on.

[0048] The Examples will now be illustrated by a the following non-limiting Examples. Examples of the invention are referred to by a number and comparative Examples by a letter. Table 1

[0049] Methods

[0050] Polished human enamel blocks (3 x 3 mm) in three, pre-made templates of n=12 were baseline SMH (Surface Microhardness) measured (HV 0.1 kgf / 10s, 5 indents per specimen). An n=12 template was assigned to each of the two treatments: Example 1 and Example A.

[0051] Each cycle, enamel specimens were exposed to a cycle of treatments as follows: (1) toothpaste in the form of a 1:2 slurry with deionised water for 2mins; (2) rinsed with deionised water; (3) exposure to artificial saliva for2hours (pH7.0, 1.5mM calcium chloride, 0.9mM potassium dihydrogenphosphate, 20mM HEPES, 130mM potassium chloride); (4) exposure to gastric acid solution for 30s (pH2.3, 10mM hydrochloric acid); (5) rinsed with deionised water.

[0052] Enamel SMH was remeasured after 2 and 4 treatment cycles. The mean enamel SMH was calculated for each specimen and the % change in enamel SMH was calculated using: 100 The overall mean % change SMH was calculated for each treatment group and time point.

[0053] Statistical analysis (ANOVA, Tukey-Kramer) was conducted using JMP 14.0.1. A smaller % change SMH means greater protection of the enamel by the product against erosive challenge.

[0054] After 2 and 4 cycles, Example 1 delivers significantly greater protection against gastric acid challenges than Example A.

Claims

CLAIMS1 . An oral care composition comprising: a) from 20 to 90wt% of the total composition of one or more organic polyols having 3 or more hydroxyl groups in the molecule; b) calcium silicate; c) a sodium phosphate salt; d) mono calcium phosphate e) xanthan gum f) carrageenan.

2. An oral care composition to claim 1 in which the level of xanthan gum is from 0.1 to 0.9wt% of the total composition.

3. An oral care composition according to claim 1 or claim 2 in which the level of carrageenan is from is from 0.1 to 0.9wt% of the total composition.

4. An oral care composition according to any preceding claim in which the level of sodium phosphate salt is from 1 to 20wt%, preferably 2 to 15 wt% of the total composition.

5. An oral care oral care composition according to any preceding claim in which the level of calcium silicate is from 1 to 30 wt%, preferably 5 to 20 wt% of the total composition.

6. An oral care composition according to any preceding claim in which the level of monocalcium phosphate is from 0.1 to 10 wt%, preferably 1 to 6 wt% of the total composition.

7. An oral care composition according to any preceding claim in which the weight ratio of xanthan gum to carrageenan is from 1 :2 to 2:1 .

8. An oral care according to any preceding claim in which the composition comprises from 0.2 to 5wt% of the total composition of one or more surfactants.

9. An oral care composition according to claim 9 in which the surfactant methyl cocoyl taurate.An oral care composition according to any preceding claim comprising from 3 to 75wt% of the total composition of one or more particulate abrasive cleaning agents. An oral care composition according to any preceding claim in which the carrageenan is a mixture of iota and kappa carrageenan. An oral care composition according to any preceding claim in which the organic polyol comprises glycerol. An oral care composition according to any preceding claim that is a toothpaste. An oral care composition as described in any preceding claim for use as a medicament to mitigate erosion of tooth enamel by gastric acid.

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