Use of oral care composition comprising a zinc compound for absorbing odours in the mouth

Abstract

An oral care composition comprising glycine and a zinc sulphate for use in adsorbing odours in the mouth.

Description

[0001] USE OF ORAL CARE COMPOSITION COMPRISING A ZINC COMPOUND FOR ABSORBING ODOURS IN THE MOUTH

[0002] The present invention relates to oral care compositions, in particular to oral care compositions comprising zinc compounds.

[0003] Background

[0004] Zinc salts have been used in some oral care compounds for a number of years.

[0005] US 5470561 discloses an anti-plaque mouthwash comprising a zinc salt and triclosan. The composition may also comprise glycine and has a pH of between 4 and 8, preferably between 5 and 7, the preferred pH being 6.

[0006] GBA-2052978 (Unilever) discloses a toothpaste comprising zinc salts with glycine and having a pH from 4.5 to 8.0.

[0007] Toothpaste compositions comprising zinc are disclosed in WO0612977. The toothpaste comprises water, a zinc salt, a chelating agent for the zinc.

[0008] US 5632972 (Williams) discloses a method for minimising damage to gingival and periodontal tissue by delivering a first component comprising zinc and a second component comprising a bicarbonate.

[0009] US2014170084 discloses that certain zinc salts when added to toothpastes comprising catechins prevent darkening of the colour of the toothpaste.

[0010] The present application has found that the presence of zinc in an oral care composition can adsorb odours in the mouth.

[0011] Description of the Invention

[0012] The present invention relates to an oral care composition comprising glycine and a zinc sulphate for use in adsorbing odours in the mouth.

[0013] A further aspect of the invention is the use of glycine and zinc sulphate in the manufacture of a toothpaste for preventing bad breath. Detailed Description of the Invention

[0014] 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’.

[0015] All amounts are by weight of the composition, unless otherwise specified.

[0016] It should be noted that in specifying any ranges of values, any upper value can be associated with any particular lower value.

[0017] 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.

[0018] Any ingredients mentioned in this application that are natural or naturally derived have been sourced from Europe.

[0019] The term “oral care composition" refers to a composition that is delivered to the oral surfaces. The composition may be a product which, during the normal course of usage, is not for the purpose of systemic administration or intentionally swallowed but is rather retained in the oral cavity for a time sufficient to contact substantially all of the dental surfaces and / or oral tissues for the purposes of oral activity.

[0020] Examples of the oral composition include a toothpaste or a dentifrice, a mouthwash or a mouth rinse, powder (e.g., tooth powder), lozenge, mint, cream, strip or gum (e.g., chewing gum), a film a topical oral gel, and a denture cleanser and the like.

[0021] Preferably the dentifrice / toothpaste is in the form of an extrudable semi-solid such as a cream, paste or gel (or mixture thereof).

[0022] In a preferred embodiment the zinc compound is zinc sulphate heptahydrate.

[0023] Preferably the level of zinc compound is from 0.1 to 4 wt% of the total composition.

[0024] More preferably the level of zinc sulphate hepta hydrate is form 1.5 wt% to 3.5wt%, most preferably 2 wt% to 3 wt% of the total composition. The composition comprises glycine. Preferable the level of glycine is from is from 1.5 wt% to 4 wt%, more preferably 2 wt% to 3.5 wt% of the total composition.

[0025] Preferably the zinc sulphate heptahydrate to glycine weight ratio is from 1 :3 to 3: 1 , more preferably the weight ratio of zinc sulphate heptahydrate to glycine is from 1 :2 to 2: 1.

[0026] 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.

[0027] 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.

[0028] 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. 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 exZeofinn; Zeodent 124 ex Huber, Sorbosil AC 77 ex Crosfield Chemicals (having an R.l. of approximately 1.440). The amount of these silicas in the total composition generally ranges from 5-60% by weight, usually 5-20% by weight.

[0029] 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 Huber Corporation under the trade designation Zeodent 165, Irish moss, iota-carrageenan, gum tragacanth, and polyvinylpyrrolidone. 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 fully hydrolysed or alcoholysed form. Preferred copolymers include Gantrez(R) polymers such as: Gantrez S-95: molecular weight 216,000; free acid;

[0030] Gantrez S-96: molecular weight 700,000; free acid;

[0031] Gantrez S-97: molecular weight 1,500,000; free acid; and

[0032] Gantrez MS-955: molecular weight 1 ,060,000; calcium / sodium salt.

[0033] 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.

[0034] 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. I n 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.

[0035] 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.

[0036] The preferred Green pigment is Phthalocyanine Green, preferably Phthalocyanine Green CI-74260.

[0037] 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%.

[0038] If the composition is a toothpaste it may be a dual phase paste, with the whitening pigments present in one phase.

[0039] 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.

[0040] 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.

[0041] In one embodiment a preferred class of oral care active for inclusion in the compositions of the invention includes 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.

[0042] A specific example of a suitable agent for the remineralisation of teeth is a mixture of a calcium source and a phosphate source which, when delivered to the teeth results in the in situ generation of hydroxyapatite on teeth.

[0043] Illustrative examples of the types of calcium source that may be used in this context (hereinafter termed “remineralising calcium sources”) include, for example, calcium phosphate, calcium gluconate, calcium oxide, calcium lactate, calcium glycerophosphate, calcium carbonate, calcium hydroxide, calcium sulphate, calcium carboxymethyl cellulose, calcium alginate, calcium salts of citric acid, calcium silicate and mixtures thereof. Preferably the remineralising calcium source is calcium silicate.

[0044] 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.

[0045] Illustrative examples of the types of phosphate source 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.

[0046] 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 remineralising phosphate source based on the total weight of the oral care composition.

[0047] Mixtures of any of the above described materials may also be used.

[0048] The composition according 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; 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.; surfactants, such as anionic, nonionic, cationic and zwitterionic or amphoteric surfactants;

[0049] 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.

[0050] Examples will now be illustrated by the following non-limiting Examples; Examples according to the inventio are illustrated by a number, comparative Examples by a letter. Examples

[0051] Formulation:

[0052] Two toothpaste formulations were prepared as outlined in the table below:

[0053] Assessment:

[0054] A 1 : 1 slurry of toothpaste and water was prepared by combining 20g of toothpaste and 20g deionised water using a Fastprep-24 mixer supplied by MP biomedical. The mixture was homogenised. The mixture was then spun in a centrifuge at6000rpm for 15 minutes to remove the solids. The separated liquid was transferred to another container.

[0055] A hydrogen sulphide solution was prepared using Aroxa 72ug hydrogen sulphide flavour tablets produced by Cara Technologies. The tablet contents were placed in a vial and made up to 7.2ml in mass with deionised water to make a 10ug / ml hydrogen sulphide solution.

[0056] To a second vial 0.01g of toothpaste slurry liquid mixture was added. To this vial 0.5ml or 1ml aliquots of hydrogen sulphide solution were added and the vial resealed. The contents were shaken by hand to mix and left for two minutes to equilibrate. After two minutes the lid was removed, and the head spaced smelled. The presence of a thiol in the headspace of the vial can be detected as a boiled or rotten egg like aroma.

[0057] Comparative Example: Colgate Max Fresh Sourced from India market. Example A:

[0058] Example B:

[0059] The data shows that an olfactory approach can successfully be used to measure the ability of zinc salts in toothpaste to bind hydrogen sulphide.

[0060] Instrument assessment

[0061] Assessment:

[0062] A 1 : 1 slurry of toothpaste and water was prepared by combining 20g of toothpaste and 20g deionised water using a Fastprep-24 mixer supplied by MP biomedical. The mixture was homogenised at 6m2 for 20 seconds. The mixture was then spun in a centrifuge at 6000rpm for 15 minutes to remove the solids. The separated liquid was transferred to another container.

[0063] A hydrogen sulphide solution was prepared using Aroxa 72ug hydrogen sulphide flavour tablets produced by Cara Technologies. The tablet contents were placed in a vial and made up to 7.2ml in mass with deionised water to make a 10ug / ml hydrogen sulphide solution.

[0064] To a second vial 0.01g of toothpaste slurry liquid mixture was added. To this vial 0.5ml or 1ml aliquots of hydrogen sulphide solution were added and the vial resealed. The contents were shaken by hand to mix and left for two minutes to equilibrate. After two minutes 1 ml of the headspace was removed with a syringe and an Oral Chroma instrument from Nissha Co Ltd (Japan) was used to measure hydrogen sulphide in the headspace.

[0065] Comparative Example: Colgate Max Fresh Sourced from India market.

[0066] Example A: Example B:

[0067] Zinc assessment

[0068] Formulation:

[0069] A toothpaste formulation was prepared as outlined in the table below:

[0070] Assessment:

[0071] A 1 : 1 slurry of toothpaste and water was prepared by combining 20g of toothpaste and 20g deionised water using a Fastprep-24 mixer supplied by MP biomedical. The mixture was homogenised. The mixture was then spun in a centrifuge at6000rpm for 15 minutes to remove the solids. The separated liquid was transferred to another container.

[0072] A hydrogen sulphide solution was prepared using Aroxa 72ug hydrogen sulphide flavour tablets produced by Cara Technologies. The tablet contents were placed in a vial and made up to 7.2ml in mass with deionised water to make a 10ug / ml hydrogen sulphide solution.

[0073] To a second vial 0.01g of toothpaste slurry liquid mixture was added. To this vial 0.5ml or 1ml aliquots of hydrogen sulphide solution were added and the vial resealed. The contents were shaken by hand to mix and left for two minutes to equilibrate. After two minutes 1 ml of the headspace was removed with a syringe and an Oral Chroma instrument from Nissha Co Ltd (Japan) was used to measure hydrogen sulphide in the headspace.

[0074] Comparative Example: Colgate Max Fresh Sourced for India market. Example 1:

[0075] A second assessment was carried out using an olfactory approach. To a vial 0.01g of toothpaste slurry liquid mixture was added. To this vial 0.5ml or 1ml aliquots of hydrogen sulphide solution were added and the vial resealed. The contents were shaken by hand to mix and left for two minutes to equilibrate. After two minutes the lid was removed, and the head spaced smelled. The presence of a thiol in the headspace of the vial can be detected as a boiled or rotten egg like aroma.

[0076] Comparative Example: Colgate Max Fresh Sourced for India market.

[0077] Example 1:

[0078] At low levels of hydrogen sulphide generation there is a certain amount of experimental noise, but as the numbers become larger trends can be assessed. The data shows that Example 1 with glycine and zinc sulphate salts can bind hydrogen sulphide in a toothpaste more effectively than a composition comprising zinc citrate, thus minimizing odour in the mouth and bad breath.

Claims

CLAIMS1. An oral care composition comprising glycine and a zinc sulphate for use in adsorbing odours in the mouth.

2. An oral care composition for use according claim 1 in which the zinc salt is zinc sulphate heptahydrate.

3. An oral care composition according to any preceding claim in which the weight ratio of zinc sulphate heptahydrate to glycine is from 1 :3 to 3: 1 , preferably 1 :2 to 2: 1.

4. An oral care composition according to any preceding claim in which the zinc compound is present at a level from 0.1 to 4 wt% of the total composition.

5. An oral care composition for use according to any preceding claim that further comprises a silica abrasive.

6. An oral care composition according to any of claims 1 to 5 that further comprises a carbonate abrasive.

7. An oral care composition for use according to any preceding claim that further comprises an anionic and / or nonionic cleansing surfactant.

8. Use of glycine and zinc sulphate in the manufacture of a toothpaste for preventing bad breath.

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