The present invention relates to an oral composition according to the preamble of claim 1.

The object of the present invention is to provide an oral composition which improves the delivery of sparingly soluble zinc citrate from an oral composition comprising an anionic surfactant.

WO02/026203 (Henkel) discloses an oral composition comprising cocoacylamidopropyl betaine and sodium lauryl sulphate. The composition also comprises zinc sulphate, a water soluble zinc salt.

Accordingly, the present invention provides an oral composition according to claim 1.

Preferably, the composition comprises the betaine derivative and the anionic surfactant in a weight ratio of from 0.95:1 to 1.05:1.

Preferably, the oral care composition according to the invention comprises from 0.001 to 5% by weight zinc citrate, more preferably from 0.5 to 3.0% by weight.

Suitable anionic surfactants are, for example, sodium alkyl sulfates containing 12 to 18 carbon atoms in the alkyl group. Other suitable anionic surfactants are alkali metal salts, preferably sodium salts of alkyl polyglycol ether sulfate containing 12 to 16 carbon atoms in the linear alkyl group and 2 to 6 glycol ether groups in the molecule, of linear alkane (C 12-18) sulfonate,•of sulfosuccinic acid monoalkyl (C 12-18 ) esters, of.sulfated fatty acid monoglycerides, sulfated fatty acid'alkanolamides, sulfoacetic acid alkyl (C 12-16').*esters, acyl sarcosines, acyl taurides and acyl isothionates containing 8 to 18 carbon atoms in the acyl group.

Suitable betaine surfactants include cocoalkyl betaine or cocoamidopropyl betaine.

Preferably the antimicrobial agent is present in an amount of from 0.01 to 5% by weight of the composition, more preferably from 0.5 to 3% by weight..

The oral composition according to the invention comprise further ingredients which are common in the art, such as:

antimicrobial agents, e.g. Triclosan, chlorhexidine, sanguinarine extract, metronidazole, quaternary ammonium compounds, such as cetylpyridinium chloride; bis-guanides, such as chlorhexidine digluconate, hexetidine, octenidine, alexidine; halogenated bisphenolic compounds, such as 2,2' methylenebis-(4-chloro~6-bromophenol), and the alkyl parabens such as n-octyl paraben and analogues thereof;

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.;

surfactants, such as anionic, noni'onic, cationic and • zwitterionic or amphoteric surfactants;

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.

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.

Liposomes may also be used to improve delivery or stability of active ingredients. The oral compositions may be in any form common in the art, e.g. toothpaste, gel, mousse, gum, cream, etc. and may also be formulated into systems for use in dual-compartment type dispensers.

The toothpaste according to the invention is made by standard processes. An example of an'oral composition according to the invention is found in the Example. It is made using processes known to the person skilled in the art.

EXStMPLE

Ingredients Amount % (w/w) Water to 100 Sorbitol ( 70%aq) 63 Sodium Fluoride 0 . 32 PEG 32 4 Zinc Citrate 2 Glycine 0 . 35 Thickening Silica 9 Abrasive Silica 4 Sodium carboxymethyl 0 . 9 cellulose Sodium Bicarbonate 2 Sodium Hydroxide 0 . 06 Cocoamidopropyl 1 betaine SLS 1