WO2018206172A1

WO2018206172A1 - Oral care compositions

Info

Publication number: WO2018206172A1
Application number: PCT/EP2018/054573
Authority: WO
Inventors: Andrew Joiner; David Thomas Littlewood; Carole Jane Philpotts
Original assignee: Unilever Plc; Unilever N.V.; Conopco, Inc., D/B/A Unilever
Priority date: 2017-05-12
Filing date: 2018-02-23
Publication date: 2018-11-15

Abstract

An oral care composition comprising an amphoteric surfactant and a pigment having a hue angle, h, in the CIELAB system of from 220 to 320 degrees.

Description

ORAL CARE COMPOSITIONS

The present invention relates to oral care compositions that enhance the white appearance of teeth.

Compositions comprising pigments that whiten the teeth are disclosed in W016099544 and WO 150975709. EP 1 935 395 discloses whitening composition comprising a pigment having a hue angle, h, in the CIELAB system of from 220 to 320 degrees and a soluble deposition aid for the pigment.

The object of the invention is to deliver an improved whitening benefit to the teeth.

Description of the Invention

In a first aspect, the present invention relates to an oral care composition comprising an amphoteric surfactant and a pigment having a hue angle, h, in the CIELAB system of from 220 to 320 degrees.

In a second aspect, the invention relates to Use of the composition according to any of the previous claims for enhanced whitening of the teeth.

Detailed Description of the Invention

Compositions according to the invention comprise a pigment having a hue angle, h, in the CIELAB system of from 220 to 320 degrees most preferably between 250 and 290 degrees. A detailed description of hue angle may be found on p57 of Colour Chemistry 3rd edition by H. Zollinger published by Wiley-VCH.

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°C. As a reasonable approximation, the relevant medium may be considered to be water and the relevant temperature to be 25°C.

Preferably, the pigment is capable of reflecting sufficient light such that the treated tooth is perceivably whiter than its initial colour. Preferably, the pigment is coloured such that its natural colour is within the violet-red to green-blue colour, preferably from violet to blue.

Preferably, the pigment is violet or blue, more preferably one of those listed in the Colour Index International. These pigments are listed as pigment violet 1 through to pigment violet 56 and pigment blue 1 through 83. The preferred pigment violets are pigment violet 1 , 1 :1 , 1 :2, 2, 3, 5:1 , 13, 19, 23, 25, 27, 31 , 32, 37, 39, 42, 44 and 50.

The preferred pigment blues are pigment blue 1 , 2, 9, 10, 14, 15, 15:1 , 15:2, 15:3, 15:4, 15:6 16, 18, 19, 24:1 , 25, 56, 60, 61 , 62 and 66.

Other suitable pigments are pigment ultramarine blue and ultramarine violet.

Preferably, the 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.

Blue covarine is especially preferred.

The amount of pigment in the composition is preferably from 0.001 to 0.3%, more preferably from 0.005 to 0.1 %, and most preferably from 0.021to 0.08% by weight. The percentage weights refer to the total amount of active present and exclude any carriers that may be present. The pigment may be uniformly spread throughout the composition or, it may be dispersed in a second phase such as a stripe or other co-extruded second phase. Compositions of the invention comprise a water soluble, polymeric deposition aid. In the context of this invention, a "water soluble" polymeric deposition aid is a material that is soluble in water, typically having a solubility of 0.5% or greater, and more typically 5% or greater by weight, at 25°C. Further, such a material remains soluble following drying - i.e. it can be re-dissolved following drying. Such materials are polymers, but are not film- forming polymers. Water solubility is required in order to avoid buildup of the deposition aid on the teeth, something that can also be a particular problem with film-forming polymers. The soluble polymeric deposition aid enhances deposition of the pigment onto the teeth and thereby enhances the colour change caused by the pigment. More particularly, a deposition agent in accordance with the invention is able to enhance the deposition of a pigment such as Blue Covarine when incorporated in a composition at a level of 0.02% by weight, particularly when the deposition aid is itself incorporated at a level of 1 % by weight.

The deposition aid is incorporated into the composition at preferably from 0.01 to 10%, more preferably at from 0.05 to 5%, and most preferably at from 0.1 to 1 % by weight. Deposition aids for use in accordance with the present invention are typically high molecular weight polymers, i.e. polymers having a molecular weight of 200,000 or greater. Preferred deposition aids are Gantrez® type polymers and high molecular weight PEGs. Particularly preferred deposition aids are Gantrez® type polymers and high molecular weight PEGs. Especially preferred deposition aids are Gantrez® type polymers.

Gantrez® type polymers 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. Gantrez® polymers themselves are available from ISP Inc. Suitable Gantrez® polymers are: 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.

Gantrez® type polymers in which the anhydride moiety is fully hydrolysed are preferred. These may be thought of as co-polymers of maleic acid and methyl vinylether. 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.

High molecular weight PEGs are poly(ethyleneglycol) polymers having a molecular weight of 1 ,000,000 or greater, preferably 2,000,000 or greater. A preferred high molecular weight PEG is Polyox 60K, a polymer having a molecular weight of

approximately 2,000,000.

The oral care composition comprises an amphoteric surfactants. Amphoteric surfactants are surfactants of which the hydrophilic group has both acid and alkaline properties, depending upon the pH of the medium in which they are present. In acid media they form cations, and in alkaline media anions. In the isoelectric pH range they are present in the form of zwitterions. Typical examples of amphoteric surfactants can be represented by the following general formula:

R,(R₂) (R₃)N-R₄-Y[JA1 ], in which R, is a fatty alkyl or acyl residue, which may be interrupted by heteroatoms, R2 and R3 are hydrogen or short alkyl residues, R contains one or more methylene units and Y is an acid residue. Many varieties exist, and the aforementioned reference contains numerous examples of amphoteric surfactants. Typical examples are the alkylglycinates, alkylproprionates, betaines, sulphobetaines, phosphatobetaines, as well as tertiary amine oxides which, although not amphoteric in structure, behave like amphoteric surfactants.

Specific examples are:

sodium cocoamphoacetate disodium cocoamphodiacetate sodium carboxy ethyl oleic polypropylamine sodium cocoamphoproprionate disodium cocoamphodiproprionate lauryl betaine cocamidopropyl betaine tallow dihydroxyethyl betaine coco sultaine coca idopropyl hydroxysultaine lauryl dimethyl amine oxide n-alkyl ethoxy dimethyl amine oxide. It is preferred if the alkyl chain of the amphoteric surfactant is coco based

Betaines are preferred as amphoteric surfactants, particularly cocamidopropyl betaine

(tegobetaine). Amphoteric surfactants are present preferably in an amount of from 0.2 to 10% by weight based on the total weight of the composition. More preferably the level of non-ionic surfactant is from 0.5 to 7 wt% of the total composition, most preferably from 1 to 5 wt% of the total composition. It is preferred if the weight ratio of amphoteric surfactant to polymeric deposition aid is from 5:1 to 40:1 , more preferably from 10:1 to 30:1 .

If other surfactants are present it is preferred if the amphoteric surfactant is at least 75wt% of the total weight of the surfactant in the composition. Although other surfactants, such as anionic and amphoteric surfactants, may be present it is preferred if they are limited to levels below 0.5 wt% of the total composition preferably less than 0.1 wt% of the total composition. This is particularly the case with anionic surfactants.

Preferably, the oral care composition comprises water, thickener and abrasive. Suitable thickeners include silicas and calcium carbonate. The preferred thickener is silica.

Preferred abrasive materials include silicas, aluminas, calcium carbonates, dicalcium phosphates, 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. The most preferred abrasives are calcium carbonate and silica, especially silica.

The oral care compositions according to the invention may comprise further ingredients which are common in the art, such as: antimicrobial agents, e.g. Triclosan, chlorhexidine, copper, zinc, and stannous salts such as zinc citrate, zinc sulphate, zinc glycinate, sodium zinc citrate and stannous

pyrophosphate, 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; 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; colouring agents; pH-adjusting agents; sweetening agents; pharmaceutically acceptable carriers, e.g. starch, sucrose, water or water/alcohol systems etc.; humectants such as glycerol, sorbitol, propyleneglycol, xylitol, lactitol etc.; binders and thickeners such as sodium carboxymethyl-cellulose, xanthan gum, gum arabic etc. as well as synthetic polymers such as polyacrylates and carboxyvinyl polymers such as Carbopol®; 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.

Liposomes may also be used to improve delivery or stability of active ingredients. The oral care compositions may be in any form common in the art, e.g. toothpaste, gel, mousse, aerosol, chewing gum, lozenge, powder, cream, and may also be formulated into systems for use in dual-compartment type dispensers. Preferred forms are toothpastes. In the following non-limiting examples, amounts are percentages by weight unless otherwise stated.

Table 1

^* Cocamidopropyl Betaine

The above formulations were used to whiten teeth as follows. Extracted human incisors and premolars were cleaned with a white toothpaste and placed in sterile saliva for two hours. After rinsing with water, baseline tooth colour was measured using a colorimeter. Tooth specimens were then brushed with a water:toothpaste slurry (2:1 ) of the test toothpastes for 60s with a toothbrush, rinsed with water and their colour remeasured. Changes in tooth colour were calculated using the WIO tooth whiteness index.

The whitening results are shown in table 2.

Table 2

Example Change in WIO

A 0.4

Claims

1. An oral care composition comprising an amphoteric surfactant and a pigment having a hue angle, h, in the CIELAB system of from 220 to 320 degrees.

2. An oral care composition according to any proceeding claim in which the alkyl chain of the amphoteric surfactant is coco based.

An oral care composition according to any preceding claim in which the amphoteric surfactant is cocamidopropyl betaine.

An oral care composition according to a preceding claim which further comprises a water soluble, polymeric deposition aid.

An oral care composition according to claim 4 in which the polymeric deposition aid comprises a co-polymers of maleic anhydride with methyl vinylether, in which the anhydride moiety may be in a partially or fully hydrolysed or alcoholysed form.

An oral care composition according to any of the preceding claims, characterised in that the deposition aid is a polymer having a molecular weight of 200,000 or greater.

An oral care composition according to any preceding claim, characterised in that the pigment has a hue angle, h, in the CIELAB system of from 250 to 290 degrees.

An oral care composition according to any preceding claim in which the pigment comprises blue covarine.

An oral care composition according to any preceding claim in which the pigment is present at a level from 0.01 to 0.3% by weight of the total formulation.

An oral care composition according to any preceding claim in which the weight ratio of amphoteric surfactant to polymeric deposition aid is from from10:1 to 30:1 .

1 1 . An oral care composition according to any preceding claim in which the amphoteric surfactant is at least 75wt% of the total weight of the surfactant in the composition.

12. An oral care composition according to any of the preceding claims, comprising water, thickener and abrasive.

13. An oral care composition according to claim 12, wherein the thickener comprises silica.

14. An oral care composition according to any of the previous claims for use in

enhancing the whiteness of the teeth.