GB2413493A

GB2413493A - Oral hygiene composition

Info

Publication number: GB2413493A
Application number: GB0409598A
Authority: GB
Inventors: Jennifer Jane Gordon
Original assignee: Glaxo Group Ltd
Current assignee: Glaxo Group Ltd
Priority date: 2004-04-29
Filing date: 2004-04-29
Publication date: 2005-11-02
Also published as: GB0409598D0

Abstract

A stable oral hygiene composition in the form of a dentifrice or a mouthwash, comprising an organopolysiloxane-based emulsion and an electrolyte. The organopolysiloxane preferably is dimethione and the electrolyte is a pyrophosphate.

Description

CB60852 241 3493

COMPOSITION

The present invention relates to a stable oral hygiene composition comprising an organopolysiloxane-based emulsion and an electrolyte.

The oral hygiene composition may be in the form of a mouthwash, or a dentifrice. The dentifrice may be in the form of a powder, toothpaste, chewing gum, cream, etc. It Is known from British Patent No GB 686429 that the incorporation of organopolysiloxanes in a dentifrice helps prevent the adhesion of, and facilitates the removal of tars, stains, tartar and the like from teeth This is due to the adherence of the organopolysiloxane, such as silicone oil, to the teeth as a thin hydrophobic film.

Dental plaque forms as a thin film on the surface of teeth, being composed of an aggregation of bacteria and a surrounding matrix. Subsequent mineralization of the plaque on the enamel surface leads to the formation of calculus. Plaque is now considered to be the prime etiological factor in the development of caries, and it is also implicated in periodontal disease. There is also an association between the presence of calculus and the incidence of periodontal disease (see Harry's Cosmeticology, 7th edition, ed J.B. Wilkinson and R.J. Moore, George Goodwin 1982, pp590-592).

The use of antimicrobial agents in oral hygiene products Is therefore desirable, since the antimicrobial agent retards the accumulation of dental plaque and hence reduces the occurrence of caries, calculus and periodontal disease. Examples of antimicrobial agents used In oral hygiene products are triclosan, chlorhexidine and cetylpyridinum chloride (CPC). One problem with the use of antmicrobials is that they tend to stain teeth Also, certain antimicrobials such as CPC and tnclosan are not strongly bound within the oral cavity and as a result their antimicrobial activity can be limited.

It is disclosed in EP 0518924 A1 that when organopolysiloxanes such as silicone oil are added together with certain antibacterial agents to a dentifrice, the organopolysloxane can act as a reservoir of the antibacterial agent which is soluble in the organopolysiloxane, either directly or indirectly. Small amounts of the antibacterial agent are slowly released from the organopolysiloxane film adhering to the teeth, thereby effectively inhibiting the formation of plaque.

Other components which are used in oral hygiene products are polishing and/or thickening agents. Commonly used polishing and thickening agents include calcium salts and/or silica. However, calcium salts and silica adsorb organopolysiloxanes such as silicone oil. This is undesirable in the oral hygiene product since the adsorbed organopolysiloxane Is prevented from forming a thin hydrophobic film on the teeth CB60852 We have found that adsorption of the organopolysiloxane by chalk and/or silica may be prevented when the silicone oil is held in an emulsion. This leaves the organopolysiloxane free to form a thin film on the teeth Preferably, the organopolysiloxane-based emulsion comprises organopolysiloxane and glycerin An electrolyte, such as an alkali metal pyrophosphate, is another desirable component of oral hygiene products. Electrolytes help prevent the build up of tartar and aid the removal of stains. It is also known from EP 0251591 A1 that by Incorporating certain levels of soluble, alkali metal pyrophosphates into the aqueous oral hygiene formulations, the adsorption of an antibacterial agent can be enhanced. Examples of alkali metal pyrophosphates include tetra sodium pyrophosphate and tetra potassium pyrophosphate If it is desired to use an electrolyte in an oral hygiene product comprising the above mentioned organopolysiloxane-based emulsion, it is found that the electrolyte causes phase separation of the emulsion, so that the oral hygiene product is unstable. An essential feature of the present invention is the use of an electrolyte in the claimed oral hygiene composition According to a first aspect of this invention there is provided a stable oral hygiene composition in the form of a dentifrice or a mouthwash, comprising an organopolysiloxane-based emulsion and an electrolyte.

The composition may be in the form of a dentifrice or mouthwash, preferably a dentifrice.

Preferably, the electrolyte comprises a pyrophosphate gel. Preferably, the pyrophosphate gel is present in an amount ranging from 30-50 % w/w of the total composition, more preferably in an amount ranging from 35-45 % w/w. Preferably the pyrophosphate gel comprises a hexahydric alcohol, water, a thickening agent and an alkali metal pyrophosphate. Preferably, the hexahydric alcohol is sorbitol Preferably, the thickening agent Is xanthan gum.

Preferably, the organopolysiloxane comprises silicone oil. Preferably, the silicone oil is present in an amount ranging from 5-15 % w/w of the total composition, more preferably in an amount ranging from 6-10 % w/w.

Preferably, the emulsion comprises silicone oil and glycerin. Preferably, the glycerin Is present in an amount ranging from 10-20 % w/w of the total composition, more preferably in an amount ranging from 12-18 % w/w.

Preferably, the emulsion is stabilised with an emulsifier. Preferably, the emulsifier is 1 %w/w polysorbate:sobitan strearate (45:55).

CB60852 Preferably, the oral hygiene composition additionally comprises an antibacterial agent Preferably the antibacterial agent is triclosan.

Preferably, the oral hygiene composition additionally comprises a further thickening agent or a polishing agent.

Examples of polishing agents are insoluble calcium salts such as calcium carbonate, dcalcium phosphate and calcium pyrophosphate; and also alumina, silica and synthetic plastics resin particles.

The silica abrasive can be a precipitated silica or a silica gel, such as the silica gels described in U.S. Patent No. 3538230. Preferred silica gels are marketed under the trade name 'Syloid' by W.R. Grace and Company, Davison Chemicals Division. Preferred precipitated silicas are those marketed under the trade name 'Zeodent' by the J.M. Huber Corporation. The pyrophosphate component (c) should have a high degree of available pyrophosphate anions, and accordingly the preferred abrasives are noncalcium based materials such as silica or alumina so as to avoid the formation of insoluble calcium pyrosphate. Calcium pyrophosphate itself, however, can be used as the abrasive since this will not lead to such difficulties. Other insoluble calcium salts can be used provided the formation of free calcium ions is suppressed, and this may be earned out using the method disclosed in EP 0092929 A2.

Thus, when the abrasive is calcium carbonate, a soluble carbonate such as sodium carbonate is included in the composition. Similarly when the abrasive is calcium phosphate, a sodium phosphate may be included.

Examples of thickening agents include sodium carboxymethylcellulose, carrageenan gum, xanthan gum, carbopol, insoluble calcium carbonate and silica.

The electrolyte preferably comprises an pyrophosphate gel, which may contain an alkali metal pyrophosphate. The alkali metal pyrophosphate may be selected from the following compounds, in hydrated or unhydrated forms: Na4P2O7, K4 P2O7, Na2K2P2O7, Na2H2P2O7, K2H2P2O7. Mixtures of any two or more of these materials may be used, the upper percentage limit of each component being dictated largely by solubility and taste considerations.

Suitable organopolyoxysilanes include fluid organopolyoxysilanes described in British Patent No 789851. A preferred class composes the diphenyl or di(C1-4)alkyl polyoxysilanes, more preferably dimethylpolyoxysilane.

CB60852 Suitable emulsifiers and combinations of emulsifiers include polyoxyethylene alkyl ethers, polysorbate and one or more sorbitan esters; sucrose esters; glyceryl monostearate and polyoxyethylene strearate; and sodium lauroyl sarcosinate Preferably, a combination of emulsifiers is employed. Preferably, the emulsifier combination Is polysorbate and one or more sorbitan esters; more preferably polysorbate and sorbitan stearate, most preferably polysorbate and sorbitan stearate (45:55).

Suitable antibacterial agents include chlorhexidine, cetylpyridinium chloride (CPC) and antiseptic phenols such as triclosan.

ionic fluorine-containing compounds may also be present in the composition of the invention, and these may include ionic fluorides, such as alkali-metal fluorides, preferably sodium fluoride, and/or ionic monofluorophosphates. A preferred ionic monofluorophosphate is an alkalimetal monofluorophosphate, especially sodium 1 5 monofluorophosphate.

When the composition contains sodium fluoride and a calcium containing abrasive, the formation of free calcium cations can be suppressed, using the method disclosed in EP 0092929 A2.

The compositions of the Invention may optionally contain other agents known to enhance the anti-canes effect of monofluorophosphate, such as calcium glycerophosphate, this being incorporated in a weight ratio of up to 1:3, preferably 1:20 to 1:3, compared to the total weight of monofluorophosphate salt.

Compositions of the present invention may be produced by admixture of the various ingredients.

The compositions of the invention will also usually contain surfactants, gelling agents and other excipients such as flavouring and colouring agents.

The surfactant is normally a water-soluble non-soap or synthetic organic detergent.

Suitable surfactants include the water-soluble salts of: higher fatty acid monoglycende monosulphates (for example sodium hydrogenated coconut fatty acid monoglycende monosulphate); higher alkyl sulphates (for example sodium lauryl sulphate); alkylarylsulphonates (for example sodium dodecylbenzenesulphonates); and higher alkyl sulphoacetates (for example sodium lauryl sulphoacetate). There may also be used the saturated higher aliphatic acyl amides of lower aliphatic amino carboxylic acids having 12 to 16 carbon atoms in the acyl radical and in which the amino acid portion is derived from the lower aliphatic saturated mono- aminocarboxylic acids having 2 to 6 carbon atoms, such as the fatty acid amides of glycine, sarcosine, alanine, 3-aminopropanoic acid and CB60852 vagina, particularly the N-lauroyl, myristoyl and palmitoyl sarcosinate compounds Conventional non-ionic surfactants may also be included, if desired.

The surface-active materials are generally present in an amount of 0.05 to 15%, preferably 0.5 to 15%, more preferably 0.5 to 5% by weight of the composition.

In general liquid components in the compositions will comprise chiefly water, glycerine, sorbitol and/or a glycol, including suitable mixtures thereof. Suitably, the glycol Is propylene glycol or a polyethylene glycol. It is preferred to use also a gelling agent in dental creams, such as natural or synthetic gums or gumlike materials, e.g Irish Moss, gum tragacanth, guar gum, sodium carboxymethylcellulose, hydroxyethylcellulose, polyvinyl pyrrolidone, starch or thickening silica. The gelling agent content is usually up to 10% and preferably 0.01 to 5% by weight of the preparation.

Other materials may be added, such as sweetening agents, for example soluble saccharin, flavouring oils such as oils of spearmint, wintergreen, peppermint, chloroform, colouring or whitening agents such as titanium dioxide, preservative such as sodium benzoate, emulsifying agents, silicones, alcohol, menthol, chlorophyll containing compounds, for example, sodium copper chlorophyllin and agents for sensitive dentine, for example strontium salts, formaldehyde.

The compositions of the invention may also be in a form of other oral hygiene compositions, for example, the ingredients may be incorporated in mouthwashes of the suspension type, or in compositions which will be chewed by the user, for example, chewing gum, tablets, pastilles and lozenges. These compositions will contain the conventional base materials together with suitable flavours and sweetening agents and may be formulated In known manner.

According to a second aspect of the invention there is provided a process for making a stable oral hygiene composition comprising the steps of: i) combining a hexabydric alcohol, water, a thickening agent and an alkali metal pyrophosphate to give a pyrophosphate gel; ii) combining silicone oil, glycerin and an emulsifier to give an emulsion; iii) combining the pyrophosphate gel and the emulsion.

Preferably, there is an additional process step of adding an antibacterial agent Preferably, the addition of the antibacterial agent is the final step.

Stable oral hygiene compositions of the invention are illustrated by the following Example.

CB60852 Ingredient Phase % w/w Sorbitol 70% (Non-crystallising) A 23.04 PEG 6 A 3.00 Tetrasodium pyrophosphate A 0 91 Tetrapotassium pyrophosphate A 2 00 Saccharin sodium A 0.20 SLS (Empicol 0045V) A 0.51 Keltrol F A 0.52 Zeofree 153B A 5.00 Zeodent 113 A 7.00 Titanium Dioxide (Cl 77891) A 0.72 L12176 flavour A 0.65 Peppermint oil, American A 0.35 Sterile Water for Irrigation A 15.08 Dimeticone EP N 8.00 Glycerin N 16. 75 Polysorbate 60 (Crillet 3 Super) N 0.11 Sorbitan stearate (Span 60) N 0.14 PEG 6 N 3.00 Triclosan N 0.30 Zeofree 153B N 5.00 Zeodent 113 N 7. 00 Titanium Dioxide (Cl 77891) N 0.72 1 00.00% A = "aqueous" phase (containing electrolyte) N = "non-aqueous phase" (emulsion)

Claims

CB60852 Clalms 1 A stable oral hygiene composition in the form of a

dentifrice or a mouthwash, comprising an organopolysiloxane-based emulsion and an electrolyte.
2 An oral hygiene composition according to claim 1 wherein the electrolyte comprises a pyrophosphate gel.
3. An oral hygiene composition according to claim 2 wherein the pyrophosphate gel comprises a hexahydric alcohol, water, a thickening agent and an alkali metal 1 0 pyrophosphate.
4. An oral hygiene composition according to claim 3 wherein the hexahydric alcohol Is sorbitol
5. An oral hygiene composition according to claim 3 or claim 4 wherein the thickening agent is xanthan gum.
6. An oral hygiene composition according to claim 1 or claim 2 wherein the organopolysiloxane comprises silicone oil.
7. An oral hygiene composition according to any preceding claim wherein the emulsion comprises silicone oil and glycerin.
8. An oral hygiene composition according to any preceding claim further comprising an emulsifier.
9 An oral hygiene composition according to claim 8 wherein the emulsifier Is 1%w/w polysorbate:sobitan strearate (45:55).
10. An oral hygiene composition according to any preceding claim which additionally comprises an antibacterial agent.
11 An oral hygiene composition according to claim 10 wherein the antibacterial agent Is triclosan.
12. An oral hygiene composition according to any of claims 3 to 11 which comprises a further thickening agent.
13. An oral hygiene composition according to any preceding claim which additionally comprises a polishing agent.

CB60852
14 Amoral hygiene composition according to claim 12 or claim 13 wherein the thickening or polishing agent is silica, an insoluble calcium salt or a combination of silica and an insoluble calcium salt.
15. An oral hygiene composition according to any preceding claim which additionally comprises one or more components selected from the list: flavouring agent, surfactant, preservative, colour, or a fluorinecontaining agent.

16 A process for making a stable oral hygiene composition comprising the steps of i) combining a hexahydrc alcohol, water, a thickening agent and an alkali metal pyrophosphate to give a pyrophosphate gel; i') combining silicone oil, glycerin and an emulsifier to give an emulsion; ii) combining the pyrophosphate gel and the emulsion.

17 A process according to claim 16 comprising the addition of an antibacterial agent 18 A process according to claim 17 wherein the addition of the antibacterial agent Is the final step