GB2307407A - Cosmetic composition containing a ceramide and a silicone carrier - Google Patents

Abstract

A liquid cosmetic composition which comprises a ceramide solubilised in a medium comprising a highly viscous silicone and a volatile silicone. The composition may be encapsulated and is used to treat the hair and scalp.

Description

COSMETIC COMPOSITION AND METHOD This invention relates to a cosmetic composition, more particularly to a composition containing ceramide and silicone for treatment of human hair to improve lustre, smoothness and ease of combing, and a method of production of such a composition.

BACKGROUND AND PRIOR ART It is generally understood that ceramides present within the intercellular lipid lamellae of the stratum corneum play an important role in the production and maintenance of the water permeability barrier of the skin. Ceramides, or substances closely related to them, have been disclosed as components of skin and haircare compositions. In particular, GB 2178312 and GB 2213723 disclose the use of natural ceramides extracted from skin in products for topical application. EP 0278505 suggests the use of such natural extracts for protecting the hair. Also, various references disclose the use of synthetic ceramides, which are similar to their natural counterparts found in skin, in cosmetic and dermatological compositions.

FR 2679770 describes how ceramides, owing to their insolubility in aqueous media, have frequently had to be formulated in anionic and/or nonionic surfactant, and propose aqueous dispersions of ceramide in quaternary ammonium cat ironic surfactant to ameliorate the reduced ease of combing previously encountered with ceramide-based formulations.

The use of silicones in hair treatment compositions to provide condition and manageability is well known and widely documented in the patent literature. However, stability of ceramide in a silicone medium has conventionally been very difficult to obtain.

SUMMARY OF THE INVENTION In a first aspect, the present invention provides a liquid cosmetic composition which comprises a ceramide solubilised in a medium comprising a highly viscous silicone and a volatile silicone.

In a second aspect, the present invention provides a method for the preparation of a liquid cosmetic composition as above defined which comprises the steps of: (i) combining a ceramide, in solid or dispersed form, with a solubilising agent, and (ii) mixing the solubilised ceramide with a highly viscous silicone and a volatile silicone.

DETAILED DESCRIPTION Compounds which are termed ceramides are members of a class of compounds which are termed " sphingoid" compounds or "sphingolipids". These are compounds which have a backbone of sphingosine or a closely related structure, to which fatty acids are linked through a amide linkage at the amino group of the sphingosine structure.

The term 'ceramide' as used herein is intended to include analogues or derivatives of ceramides, such as glucosylceramides, to which saccharide groups are linked to the terminal hydroxyl of the sphingosine structure through a glycosidic bond, and the synthetic ceramide-like structures known as pseudoceramides. Also included are mixtures of ceramides (naturally occurring ceramides are normally obtained as mixtures), and mixtures of ceramide(s) with other lipid components, such as phospholipids and glycolipids, and/or sterols, such as cholesterol, sitosterol, stigmasterol and ergosterol, especially cholesterol.

Ceramides are preferably selected from ceramides having the general structure (1)

where A represents -CH2-; CHOR's-; -CH=CH- or -CHOY R' represents a linear or branched, saturated or unsaturated aliphatic hydrocarbon group having from 1 to 49 carbon atoms, preferably from 12 to 49 carbon atoms, or a subgroup (2).

Y - 0 - (CaHb) - (2) Razz represents a linear or branched, saturated or unsaturated aliphatic hydrocarbon group having from 8 to 28 carbon atoms, preferably from 13 to 28 carbon atoms; R 2 R'3, and R'5 individually represent H, a phosphate residue or a sulphate residue; R'4 represents H, a phosphate residue, a sulphate residue or a sugar residue; a is an integer of from 7 to 49, preferably from 12 to 49; b is an integer of from 10 to 98, preferably from 24 to 98; m is 0 or 1; Y represents H or a residue of a C14-22 fatty acid having the general structure (3).

where Z is - OH or an epoxy oxygen x is an integer of from 12 to 20 y is an integer of from 20 to 40 and z is 0 or an integer of from 1 to 4 Ceramides having the general structure (1) are naturally occurring and can be isolated from a suitable plant source or from animal tissue such as pig skin or neural tissue.

Ceramides can also be synthesised.

Particular preferred examples are ceramides I, II and III.

Pseudoceramides are preferably selected from pseudoceramides (ie synthetic ceramide like structures) having the general structure (4);

where B represents - OCH2 - or CHOH; Ra 6 represents a linear or branched, saturated or unsaturated aliphatic hydrocarbon group having from 1 to 49 carbon atoms R'6 represents a linear or branched, saturated or unsaturated aliphatic hydrocarbon group having from 1 to 49 carbon atoms, preferably from 12 to 49 carbon atoms or the subgroup (2).

R', represents a linear or branched, saturated or unsaturated aliphatic hydrocarbon group having from 8 to 28 carbon atoms preferably from 13 to 28 carbon atoms.

R' 8 represents H, or a subgroup - (CH2)cCOOH, where c is an integer of from 1 to 6, or a subgroup having the structure (5).

where X1, X2 and X3 each individually represent H, a C1.5 alkyl or a C1.5 hydroxyalkyl; d is 0 or an integer of from 1 to 4 e is 0 or 1 n is 0 or 1 and p is 0 or 1; R'g represents H, a phosphate residue, a sulphate residue or a sugar residue.

Phospholipids may be advantageously used as further lipid components in ceramide mixtures because they are derivable from plant sources. An example of a suitable phospholipid material is a mixture of phospholipids derived from a particular fraction in a continuous soya bean phospholipid extraction and is sold under the trade name Ceramax by Quest International of Ashford, Kent, UK.

A particularly preferred mixture is CERAMIDES LS 3773 (glycosphingolipids, phospholipids and cholesterol) ex Serobiologiques.

The level of ceramide present in compositions of the invention is suitably from 0.00001 to 1%, preferably 0.0005 to 0.5%, eg 0.01% by weight based on total weight of the composition.

The highly viscous silicone is preferably a silicone gum.

Suitable silicone gums for use in compositions of the invention include high molecular weight alkylpolysiloxane, arylpolysiloxane and alkylarylpolysiloxane, having a viscosity greater than 100,000 centistokes (cSt), preferably greater than 500,000 cSt. Included are silicone gums having end groups such as hydroxyl, such as those which have the CTFA designation dimethiconol. A particularly preferred source of these polymers is the material available as DC 1401 ex Dow Corning.

Aminofunctional silicones which have the CTFA designation amodimethicone, are also suitable for use in the compositions of the invention. Especially preferred is the polymer known as "trimethylsilylamodimethicone", available as Q2 8220 ex Dow Corning.

Mixtures of any of the above highly viscous silicones may be used. An especially preferred mixture is that of dimethiconol gum and trimethylsilylamodimethicone.

The level of highly viscous silicone in compositions of the invention is suitably from 0.1 to 30%, preferably from 0.3 to 10% by weight based on the total weight of the composition.

silicones suitable for use in compositions of the invention are those which have a boiling point in the range of about 99"C to about 260"C and a solubility in water of less than about 0.1%. These volatile silicones may be either a cyclic or a linear polydimethylsiloxane. The number of silicone atoms in the cyclic silicones is preferably from about 3 to about 7, most preferably 4 or 5. The general formula for cyclic silicones is:

wherein n = 3-7. Linear polydimethyl siloxanes useful in the invention have from about 3 to about 9 silicon atoms and have the general formula: (CH3)3Si - 0 - (-Si (CH3)2 - ~}n - Si (CH3)3 wherein n = 1-7.

Mixtures of any of the above volatile silicones may be used.

Silicones of the above type are available, for example, from Dow Corning as DC 244,245,344,345 and 200 fluids (cyclopolymethylsiloxane blends) and 200/5 fluid (a very short linear polydimethylsiloxane).

The level of volatile silicone present in compositions of the invention is generally from 50 to 99.5%, preferably from 80 to 95%, by weight based on the total weight of the composition.

composition.

The weight ratio of highly viscous silicone to volatile silicone in compositions of the invention is typically from 1:50 to 1:2, preferably 1:45 to 1:20, eg 1:35.

In compositions of the invention, the ceramide is solubilised in the silicone medium. This is suitably achieved with a solubilising agent comprising a C12 - C1s alcohol benzoate, eg the material available as FINSOLV TN, ex Fintex. The level of solubilising agent is typically from 0.1 to 30%, preferably 0.5 to 5%, eg 2 to 3% by weight based on the total weight of the composition.

According to the method of the invention, the ceramide is combined in solid or dispersed form with the solubilising agent, and the solubilised ceramide mixed with the highly viscous silicone and volatile silicone.

In a preferred method, the ceramide is combined in dispersed form with the solubilising agent. The content of ceramide in the dispersion is suitably from 2 to 30%, preferably from 5 to 15%, eg 10% by weight based on total weight of the dispersion. A suitable dispersant for the ceramide in the dispersion is a straight-chained mono carboxylic acid having 14 to 30 carbon atoms, preferably palmitic, oleic, isostearic or stearic acid or mixtures thereof. The most preferable dispersant is stearic or isostearic acid. The level of dispersant is suitably from 98 to 70%, preferably from 95 to 75%, eg 90% by weight based on the total weight of the dispersion.

The types and levels of the highly viscous silicone and volatile silicone used in the method of the invention are as hereinabove described.

Product Form Compositions of the invention have the advantage of transparency or semi-transparency, which is a highly desirable attribute for cosmetic and personal care formulations. They are also homogenous and storage stable.

Most preferably, the compositions are in encapsulated form.

The invention accordingly provides a capsule containing the cosmetic composition as herein defined. The composition may thus be conveniently delivered by rupturing of the capsules at the site of application, eg the hair and/or scalp, during use. Typically the composition is packaged in capsules consisting of a cosmetically acceptable water soluble polymeric wall material, which encapsulates a continuous liquid core comprising the composition of the invention. Most preferably the wall material is comprised of gelatin, or similar material. The liquid capacity of the capsules is suitably from 0.1 to 10 ml, preferably 0.5 to 5ml, eg lml.

The capsules comprising the composition of the invention may be applied directly to the site of application, eg the hair and/or scalp, in this form. Alternatively, the capsules may be incorporated into a conventional cosmetic composition for topical application, such as a shampoo, conditioner cream, or lotion formulation for the hair.

The invention will now be illustrated by the following nonlimiting Examples. All percentages are by weight unless otherwise specified.

Examples 1 to 3 Hair treatment formulations were prepared containing the following ingredients shown below in Table 1:

EXAMPLE 1 2 3 INGREDIENT PERCENTAGE BY WEIGHT DC 1401'2' 5.000 5.000 5.000 DC 344t2 > 91.990 91.990 91.990 Q2 8220(3) 1.000 1.000 1.000 Finsolv TN4 2.000 2.000 2.000 Ceramide II( 0.010 Ceramides LS 3773(6) 0.010 Cerasperse III(7) 0.010 (1) A mixture of cyclomethicone and dimethiconol ex Dow Corning.

(2) Cyclomethicone ex Dow Corning.

(3) Trimethylsilyl amodimethicone ex Dow Corning.

(4) Cl2-Cls alcohol benzoak, ex Fintex (5) N-Hexadecanoyl-2-aminohexadecan-1,3-diol, ex Quest.

(6) Glycosphingolipids, Phospholipids and Cholesterol ex Serobiologiques.

(7) N-stearoyl-phytosphingosine (10%) in isostearic acid, ex Gist-brocades.

The compositions of Examples 1 to 3 were prepared by dissolving the ceramide in the Cl2-Cls alcohol benzoate, and mixing the solution thus obtained with the cyclomethicone/dimethiconol and cyclomethicone.

The compositions were all transparent, homogeneous and showed no precipitation of ceramide after storage in glass bottles for 8 weeks at temperatures of 370C and 450C.

Sensorv Evaluation of Drv Properties The composition of Example 3 was tested for various dry hair attributes by a trained panel of assessors using a paired comparison technique. Each panellist was presented a hair switch washed with a conventional shampoo (control), and a switch washed with the same shampoo and then treated with the composition of Example 3. The results are shown below in Table 2: TABLE 2

ATTRIBUTE t CHOSEN * CONTROL EXAMPLE 3 SMOOTHNESS 0 100 SHINE 0 100 EASE OF DRY COMBING 15 85 * Sign. diff. p < 0.001.

In Vitro Measurements of Detanalina Wet Hair (Total Combina Time) Switches washed with a conventional shampoo (control) were tested in-vitro for Total Combing Time (TCT) against switches washed with the same shampoo and then treated with the composition of Example 3. The results are shown below in Table 3.

TABLE 3 % TCT *

CONTROL 90 EXAMPLE 3 35 * The lower the % TCT, the higher the conditioning benefits obtained from the product. Sign. diff. p < 0.01.

Claims (10)

1. A liquid cosmetic composition which comprises a ceramide solubilised in a medium comprising a highly viscous silicone and a volatile silicone.

2. A composition according to claim 1 in which the ceramide is selected from the group consisting of ceramide II, ceramide III and a glycosphingolipid/phospholipid/cholesterol mixture.

3. A composition according to claim 1 or 2 in which the highly viscous silicone is a silicone gum.

4. A composition according to any preceding claim in which the volatile silicone is a mixture of cyclic silicones having from 3 to 7 carbon atoms.

5. A composition according to any preceding claim in which the level of ceramide present is from 0.0005 to 0.5% by weight based on total weight of the composition.

6. A composition according to any preceding claim in which the weight ratio of highly viscous silicone to volatile silicone is from 1:45 to 1:20.

7. A composition according to any preceding claim in which the ceramide is solubilised in the silicone medium with a C22 - C15 alcohol benzoate.

8. A composition according to any preceding claim which is transparent.

9. A method for the preparation of a liquid cosmetic composition as defined in any one of claims 1 to 8 comprising the steps of: (i) combining a ceramide, in solid or dispersed form, with a solubilising agent1 and (ii) mixing the solubilised ceramide with a highly viscous silicone and a volatile silicone.

10. A capsule for topical application to the hair and/or scalp containing a composition as defined in any one of claims 1 to 8.