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[ EN ]

The present invention relates to an oral composition which comprises capsules containing keratin.

Compositions for use in personal care, which comprise capsules containing keratin, are known in the art . JP 10/337,466 (Akusenu) discloses their use in cosmetic
formulations. The capsules described therein comprise water soluble keratin as an improved wall material. The keratin is in the form of microfibrils of molecular weight between 35,000 and 60,000.

While keratin is a desirable ingredient in personal product compositions it is preferred that it is the core of the capsule which contains keratin as it is the core which is released when the capsule is burst.

Unfortunately, the inclusion of ingredients as a core material is not easy, particularly when the wall is
manufactured in the presence of the ingredients intended to be encapsulated. Keratin presents such a problem and
interferes with wall formation when it is included in the reaction mixture. This results in weaker walls, which means that the capsules are more likely to break during
manufacture, storage and dispensing. A capsule which is unstable during these stages is unsuitable as a delivery vehicle .

We have surprisingly found that the encapsulation of keratin can be much improved by using an insoluble form of keratin.

Accordingly, the present invention provides an oral
composition comprising capsules, which capsules contain keratin, characterised in that the keratin is substantially insoluble in water.

Capsules according to the invention typically comprise a core surrounded by an encapsulating wall. By containing keratin is meant that the keratin is contained in the core of the capsule so it can be released when the capsule wall is ruptured.

Such an insoluble form of keratin is available commercially from Freeman Chemical Corp.

In a particularly preferred embodiment the keratin is in the form of water insoluble particles the majority of which have a diameter no greater than 75 μm, more preferably, no greater than 50 μm. To obtain such small keratin particles it may be necessary to sieve them through a suitably gauged sieve.

The oral composition according to the invention typically comprise from 0.001 to 2% by weight, preferably from 0.01 to 1% by weight water- insoluble keratin.

In a particular embodiment the capsules according to the invention additionally comprise as core material an oil . Suitable oils include vegetable oils, mineral oils, silicone oils and hydrocarbon oils. Vegetable oils are particularly preferred, especially sunflower oil, safflower oil, rape seed oil and soybean oil.

Preferably the capsules' weight average particle size ranges from 600 to 1400 μm, more preferably from 700 to 1200 μm.

Typical encapsulating materials are common in the art and include but are not limited to cyclodextrin, gum arabic, gelatin, casein, albumin, fibrinogen, xanthan gum,
haemoglobin, soluble collagen peptides, sodium alginate, carboxy-methyl cellulose, carrageenan, polyvinylpyrrolidone and similar natural or synthetic polymeric materials. Many suitable encapsulating materials are cross-linked. Cross-linking may be inherent in the encapsulating material or it may be achieved by a cross-linking agent, e.g.
glutaraldehyde .

The capsules can be made by any conventional
microencapsulation process, preferably by complex
coacervation. The process conditions and encapsulating materials should be carefully chosen, so that capsules are obtained which are neither too hard to survive any crushing during use, nor too soft to crush already during manufacture of the oral care composition.

The encapsulating materials should be stable in the presence of anionic surfactants, e.g. sodium lauryl sulphate, which is commonly included in oral compositions as a foaming agent. Such encapsulating materials preferably include gum arabic, gelatin and mixtures and derivatives thereof.

In a most preferred embodiment the encapsulating material is a mixture of gum arabic and gelatin, preferably a 50%-50% mixture .

Typical agents which may be encapsulated in addition to the keratin include any agent capable of exhibiting a
therapeutic, sensory, protective or cosmetic effect and include antimicrobial agents, anti -caries agents, gum protection agents, flavours, colours, whitening agents and suchlike.

The particle size of the capsules can be measured using conventional methods, for example, standard gauge sieves and microscopy.

Typically, the encapsulated agent will comprise from 0.01 to 10%, preferably from 0.1 to 5% and more preferably from 0.1 to 2% by weight of the oral composition according to the invention.

The oral composition according to the invention 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;

other 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, nonionic, 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.

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®;

polymeric compounds which can enhance the delivery of active ingredients such as antimicrobial agents can also be
included. Examples of such polymers are copolymers of polyvinylmethylether with maleic anhydride and other similar delivery enhancing polymers, e.g. those described in DE-A-3, 942, 643 (Colgate) ;

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 composition may be in any form common in the art, e.g. toothpaste, gel, mousse, aerosol, gum, lozenge, powder, cream, etc. and may also be formulated into systems for use in dual -compartment type dispensers.

In a preferred embodiment the oral composition according to the invention is a gel, preferably a visually clear gel.

The present invention will be further illustrated by way of example. The capsules are, preferably, made by complex coacervation with the sieved, water- insoluble keratin particles included in the coacervation reaction mixture


The following dentifrice formulation represents a formulation according to the invention:

Mass %
Sorbitol syrup (70%) 62.00
Abrasive silica 8.00
Thickening silica 8.00
Polyethylene glycol (MW 1,500) 4.00
Sodium laurylsulphate 1.80
Flavour oil 1.20
Sodium monofluoro phosphate 1.12
Sodium saccharin 0.20
Capsules comprising keratin* 1.00
(average weight particle size 800-1000 μm)
Thickener (SCMC) 0.60
Water 12.08

*the keratin comprises 0.5% by weight of the total composition.