WO2023227282A1

WO2023227282A1 - Oral care composition

Info

Publication number: WO2023227282A1
Application number: PCT/EP2023/059538
Authority: WO
Inventors: Gianni CAMPI; Michela SAVOCA; Francesca Topi
Original assignee: Unilever Global IP Ltd; Unilever IP Holdings BV; Conopco Inc
Current assignee: Unilever Global IP Ltd; Unilever IP Holdings BV; Conopco Inc
Priority date: 2022-05-25
Filing date: 2023-04-12
Publication date: 2023-11-30
Anticipated expiration: 2024-11-25
Also published as: CN119317421A; EP4532037A1

Abstract

A toothpaste composition comprising: i) 40 wt% or greater of the total composition of water, ii) silica abrasive, iii) from 0.05 wt% to 0.15 wt%, of the total composition of sodium fluoride, iv) from 0.4 wt% of the total composition of zinc sulphate.

Description

ORAL CARE COMPOSITION

Field of the Invention

The present invention relates to oral care compositions in particular oral care that are free from preservatives.

Background of the Invention

A key attribute for oral care products is that they are free from microbial and fungal contamination. Thus, there is a need for oral care products that provide consistent and reproducible resistance to bacterial growth and mould, while maintaining their efficacy and consumer acceptability. Oral care products having a high water content and a silica abrasive can be difficult to preserve, especially in the absence of preservatives.

WO 2013/095370 provides oral care compositions comprising: greater than 50 weight % water; an effective amount of benzyl alcohol; and a silica abrasive that are said to provide adequate preservation.

WO 2018/145988 discloses compositions oral care comprising low levels of sodium fluoride.

WO 2014/100930 discloses the use of a water-soluble source of stannous ions for improving the robustness towards microbial challenge of oral care compositions.

Toothpastes that contain higher levels of water are desirable from both a cost and sustainability point of view. There is now a consumer preference for products that minimise the use of preservatives and lower the level of fluoride, thus products that are self-preserving are desirable.

Description of the Invention

The present invention relates to a toothpaste composition comprising: i) 40 wt% or greater of the total composition of water, ii) silica abrasive, iii) from 0.05 wt% to 0.15 wt%, of the total composition of sodium fluoride, iv) 0.4 wt% of the total composition of zinc sulphate. The invention further relates to the use of zinc sulphate to mitigate fungal contamination in a toothpaste composition comprising 40wt% or greater of water of the total composition of water and from 0.05 wt% to 0.15 wt% the total composition of fluoride.

Detailed Description of the Invention

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”.

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

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

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.

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

In the context of the present invention the term “free from” can be interpretated as comprising less than 0.05 wt% of the total composition of an ingredient, preferably less than 0.01wt %.

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.

The toothpaste is in the form of an extrudable semi-solid such as a cream, paste or gel (or mixture thereof). 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.

The toothpaste, comprises a silica based abrasive. 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.

Compositions according to the invention comprise 0.4 wt% of the total composition of zinc sulphate, preferably the level zinc sulphate is from 0.5 to 3 wt%, more preferably from 0.6 to 1 .5 wt% of the total composition of the total composition. It is preferred if the zinc sulphate is zinc sulphate hepthydrate.

Other metal salts may be present but preferably zinc sulphate is present at all level of 60 wt% or greater the amount of zinc salts, more preferably it is the only zinc salt present. If present other metal salts include zinc chloride, zinc fluoride, zinc citrate, zinc lactate, zinc oxide, zinc monoglycerolate, zinc tartrate, zinc pyrophosphate and zinc maleate. Stannous ions such as stannous fluoride and stannous chloride may also be suitable for use with the invention.

Toothpaste compositions may further comprise a polyol at a level from 5 to 35, preferably 10 to 30 wt% of the total composition. Preferably the polyol is selected from glycerol, sorbitol mixtures thereof. Particularly preferred is sorbitol.

Compositions of the invention comprises is sodium fluoride at a level rorm 0.05 wt% 0.15 wt% the total composition of sodium fluoride., preferably from 0,07wt% to 0.13wt% of the total composition. Preferably the level of fluoride is below 800ppm, more preferably from 300 to 600 ppm.

It is preferable that the composition is free from other sources of fluoride but if present they may be sources such as stannous fluoride, sodium monofluorophosphate, zinc ammonium fluoride, tin ammonium fluoride, calcium fluoride, cobalt ammonium fluoride and mixtures thereof.

Preferably the toothpaste is free from sodium benzoate and/or benzoic acid.

A composition according to the invention will generally contain further ingredients to enhance performance and/or consumer acceptability, in addition to the ingredients specified above. 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 copolymers 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;

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

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

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

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

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

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; cetylpyridium chloride clay complex 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; opacifying agents; hyaluronic acid; amino acids such as arginine; glycine 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; 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.

The invention will now be illustrated by the following non-limiting Examples. Example according to the invention are illustrated by a number, comparative Examples by a letter.

Examples

Examples were formulated as in the tables below. They were tested for mould contamination using the methodology in ISO 11930 Cosmetics - Microbiology- Evaluation of the antimicrobial protection of a cosmetic product.

Table 1

Table 2

Table 3

Table 4

The results show that Examples according to the invention are markedly better at mitigating fungal contamination compared with the comparative Examples.

Claims

1. A toothpaste composition comprising: i) 40 wt% or greater of the total composition of water, ii) silica abrasive, iii) from 0.05 wt% to 0.15 wt%, of the total composition of sodium fluoride, iv) from 0.4 wt% of the total composition of zinc sulphate.

2. A toothpaste composition according to claim 1 further comprising a polyol at a level from 5 to 35wt%, preferably 10 to 30 wt% of the total composition.

3. A toothpaste composition according to claim 1 or claim 2 in which the polyol is selected from glycerol, sorbitol mixtures thereof.

4. A toothpaste composition according to claim 3 in which the polyol is sorbitol.

5. A toothpaste composition according to any preceding claim that is free from sodium benzoate.

6. A toothpaste composition according to any preceding claim that is free from benzoic acid.

7. A toothpaste composition according to any preceding claim in which the level zinc sulphate is from 0.5 to 3 wt% of the total composition.

8. A toothpaste composition according to any preceding claim in which the level of zinc sulphate is from 0.6 to 1.5 wt% of the total composition.

9. A toothpaste composition according to any preceding claim in which the zinc sulphate is zinc sulphate heptahydrate.

10. A toothpaste composition according to any preceding claim that comprises from 0,07wt% to 0.13wt% of the total composition of sodium fluoride. Use of zinc sulphate to mitigate fungal contamination in a toothpaste composition comprising 40wt% or greater of water of the total composition of water and from 0.05 wt% to 0.15 wt% the total composition of sodium fluoride.