WO2001070188A1

WO2001070188A1 - LOW pH HIGH FATTY ACID VANISHING CREAM

Info

Publication number: WO2001070188A1
Application number: PCT/EP2001/002344
Authority: WO
Inventors: Rully Anjasmara Siswoyo; Dwiwahyu Haryo Suryo
Original assignee: Unilever Plc; Unilever Nv; Hindustan Lever Limited
Priority date: 2000-03-21
Filing date: 2001-03-01
Publication date: 2001-09-27
Also published as: AU2001256180A1; GB0006866D0; ZA200206537B

Abstract

Cosmetic vanishing cream compositions having a pH from 1 to 6.5 are disclosed comprising relatively high concentrations of a C12-C20 fatty acid and a C8-C22 fatty acid saccharide which functions as a stabilizing agent. Acidic skin benefit agents such as alpha- and beta- hydroxy carboxylic acids may also be formulated into the compositions.

Description

LOW pH HIGH FATTY ACID VANISHING CREAM

The present invention relates to stably suspended cosmetic vanishing creams of low pH.

Vanishing creams are popular around the world because they spread easily onto the skin giving a thin, semi-matte film which seems to disappear or "vanish". They are also used to counteract shine which may arise from overactive sebaceous glands. Moreover, these creams counteract skin dryness to alleviate flaking, cracking and roughness.

The creams are usually formulated with high levels of steaπc acid suspended in water by means of an emulsifying agent. Typically the emulsifying agent is a potassium or sodium soap formed by the m si tu reaction of caustic potash or other alkali on a portion of the stearic acid. Consequently, the formulations have a pH above 7, and usually substantially above, because of the presence of alkali. Humectants, such as glycerin, are normally also present in vanishing creams.

Emerging trends in skin care have required that vanishing cream formulations be adapted to incorporate skin benefit agents. For example, WO 99/37280 (Bartolone et a l . ) discloses vanishing creams which are formulated to include alkali or alkaline earth metal salts of alpha-hydroxy carboxylic acids into order to achieve skin lightening properties. The disclosure describes the new products as having a pH above 5. Care was taken in this prior art document not to incorporate acid versions of the alpha- hydroxy carboxylic acids into the formulations. Unfortunately, the beneficial properties of these skin benefit agents have not been realized in such formulations and thus, it was clear that further work was necessary in order to enhance the performance of vanishing creams.

In addition to alpha-hydroxy carboxylic acids it would also be desirable to incorporate other skin benefit agents. For example, U.S. Patent 5,482,710 (Slavtcheff et al . ) discloses the use of alpha- and beta-hydroxycarboxylic acids m combination with salts of glycyrrhizinic acid, alpha- bisabolol and anti-microbial agents including tπclosan.

Accordingly, the present invention aims to provide a vanishing cream having a relatively high level of fatty acid and a low pH to accommodate acidic skin benefit agents which enhance the performance of the formulation.

The present invention also aims to provide a cosmetic composition, particularly a vanishing cream of low pH, wherein skin benefit agents can be stably suspended in the composition .

These and other objects of the present invention will become more readily apparent from consideration of the following summary and detailed description. A cosmetic composition is provided comprising:

(I) from 5 to 50% by weight of a C12-C20 fatty acid;

(II) from 0.1 to 20% by weight of a C8-C22 fatty acid substituted sacchaπde; wherein the composition has a pH from about 1 to about 6.5.

The applicants have surprisingly found that cosmetic vanishing creams can be stably formulated at a pH of about

6.5 or less by incorporation of a stabilizing amount of a

C8^~C22 ^^{attv acl}d substituted saccharide. Vanishing creams of the present invention which have a high fatty acid content (over 5% of, for example, steaπc acid) retain the traditional consumer benefits of such products even at low pH, namely good moisturization without greasiness/oiliness, ease of absorption, cool sensation and a matte finish. Addition of acidic skin benefit agents results in improvements in the areas of rough/flaky skin, enhancement of skin cell renewal and reduction of pimples.

Consequently, a first essential component of the vanishing cream compositions of the present invention is a C12-C20 fatty acid, preferably steaπc acid. The fatty acid will be present m amounts ranging from 5 to 50%, preferably from 7 to 40%, more preferably from 10 to 25%, optimal] y from 12 to 20% by weight of the composition. A second component of the vanishing cream compositions of the present invention is a C₈-C₂₂ fatty acid substituted sacchaπde. Preferably, these components are CB-C₂2 fatty acid substituted glucose materials, more preferably C₈-C₂₂ fatty acid and C₁-C₃ alkyl substituted glucose compounds.

Suitable Cβ-C2₂ fatty acid substituted sacchaπdes include methyl glucose sesquistearate, ethyl glucose sesquistearate, propyl glucose sesquistearate, methyl glucose sesquipalmitate, ethyl glucose sesquipalmitate, propyl glucose sesquipalmitate, methyl glucose sesquilaurate, ethyl glucose sesquilaurate, propyl glucose sesquilaurate, methyl glucose sesquibehenate, ethyl glucose sesquibehenate, propyl glucose sesquibehenate and any combinations thereof. Of these, the most preferred sacchaπde is methyl glucose sesquistearate (a CTFA and INCI nomenclature) available as TEGO Care PS sold by Th. Goldschmidt AG . Amounts of the stabilizing agent may range from about 0.1 to about 20%, preferably from about 0.5 to about 10%, more preferably from about 1 to about 8%, optimally from about 2 to about 5% by weight of the composition.

An optional but advantageous substance which may be present in compositions of the present invention is an acidic skin benefit agent. Representative of this category are the alpha- and beta- hydroxy carboxylic acids. Illustrative of the beta-hydroxy carboxylic acids is salicylic acid. The alpha-hydroxy carboxylic acids are represented by formula I having the structure:

wherein R and R may be the same or different and are selected from H, F, Cl, Br, alkyl, aralkyl or aryl groups which may be saturated or unsaturated, lsomenc or nomsomeric, straight or branched chain, having 1 to 25 carbon atoms, or in a cyclic form having 5 or 6 ring members. In addition, R and R may be substituted with an

OH, CHO, COOH or alkoxy group having 1 to 9 carbon atoms. The alpha-hydroxy acid exists as a free acid, and includes stereoisomers, and D, L, and DL forms thereof when R and R¹ are not identical.

Illustrative of this group of materials are:

2-hydroxyethanoιc acid (glycolic acid) ;

2-hydroxypropanoιc acid (lactic acid); 2-methyl 2- hydroxypropanoic acid (methyllactic acid) ; 2-hydroxybutanoιc acid; 2-hydroxypentanoιc acid; 2-hydroxyhexanoιc acid; 2-hydroxyheptanoιc acid; 2-hydroxyoctanoιc acid; 2- hydroxynonanoic acid; 2-hydroxydecanoιc acid; 2- hydroxyundecanoic acid; 2-hydroxydodecanoιc acιd(alpha- hydroxylauric acid) ; 2-hydroxytetradecanoιc acid (alpha- hydroxymyπstic acid) ; 2-nydroxyhexadecanoιc acid (alpha- hydroxypalmitic acid); 2-hydroxyoctadecanoιc acιd(alpha- hydroxystearic acid) ; 2-hydroxyeιcosanoιc acid (alpha- hydroxyarachidonic acid) ; 2-phenyl 2-hydroxyethanoιc acid (mandelic acid); 2,2-dιphenyl 2-hydroxyethanoιc acid (benzilic acid) ; 3-phenyl 2-hydroxypropanoιc acid (phenyl lactic acid); 2—phenyl, 2-methyl, 2-hydroxyethanoιc acid (atrolactic acid); 2- (4 ' -hydroxyphenyl) 2-hydroxyethanoιc acid; 2- (4 ' -chlorophenyl 2-hydroxyethanoιc acid; 2-(3'- hydroxy- ' -methoxyphenyl) 2-hydroxyethanoιc acid; 2-(4'- hydroxy-3' -methoxyphenyl) 2-hydroxyethanoιc acid; 3'-(2- hydroxyphenyl) 2-hydroxypropanoιc acid; 3- ( ' -hydroxyphenyl) 2-hydroxypropanoιc acid; and 2- (3' , ' -dihydroxyphenyl) 2- hydroxyethanoic acid.

Most preferred of this group of materials are glycolic acid, lactic acid, 2-hydroxyoctanoιc acid or combinations thereof. Levels of alpha-hydroxy alkanoic acids may range from about 0.1 to about 10%, preferably between about 0.2 and 4%, optimally between about 0.4 and 1% by weight of the composition.

In a particularly preferred embodiment, there will be present a mixture of both a beta-hydroxy carboxylic acid and an alpha-hydroxy carboxylic acid. For instance, the optimum combination is a mixture of salicylic acid and glycolic acid in a relative weight ratio from about 20:1 to about 1:20, preferably from about 10:1 to 1:1, optimally from about 3:1 to about 2:1.

Compositions of the present invention may also include a variety of anti-irritancy agents, particularly to counteract any irritancy caused by the acidic skin benefit agents. Suitable anti-irritancy agents include gluconolactone, borage seed oil, wild borage, dextran, alpha-bisabolol (extracted from chamomille), azulene (extracted from yarrow), resveratrol, petroselenic acid, and combinations thereof. Each of these may be present at levels ranging from about 0.0001 to about 5%, preferably from about 0.001 to about 1%, optimally from about 0.01 to about 0.5% by weight of the composition.

Herbal extracts may also be included as components of the composition and are particularly effective for controlling the level of sebum/oil. Suitable extracts include dill, horseradish, oats, neem, beet, broccoli, tea, pumpkin, soybean, barley, walnut, flax, ginseng, poppy, avocado, pea, sesame, dandelion, wheat, nettle, cashew, pineapple, apple, asparagus, Brazil nut, chickpea, grapefruit, orange, cucumber, buckwheat, strawberry, ginko, tomato, blueberry, cowpea and grape extracts.

Other suitable herbal extracts include ivy horse chestnut, centella asiatica, rosmaπnic acid, seπcoside, ruscogenin, escin, escolin, betulinic acid, catechin and derivatives thereof. Each of these may be present in an amount ranging from about 0.00001 to about 2%, preferably between about 0.01 and about 0.5% by weight of the composition.

Anti-microbial agents may also be useful in compositions of the present invention. Typically the anti-microbial agents are selected from tπclosan, tricarbanilide, tea tree oil, farnesol, farnesol acetate, hexachlorophene, C₄-C₂₀ quaternary ammonium salts such as benzalconium chloride and a variety of zinc or aluminum salts. Typically the zinc or aluminum salts are compounds such as zinc pyπdmethione, zinc sulphate, zinc chloride, zinc phenolsulphonate, aluminum chloride, aluminum sulphate and aluminum chlorhydrate . The anti-microbial agent may be present in amounts ranging from about 0.1 to about 5%, preferably from about 0.2 to about 1%, optimally about 0.3% by weight of the composition.

Compositions of the present invention ordinarily contain water as a carrier in amounts ranging from about 5 to about 95%, preferably from about 30 to about 90%, optimally from about 50 to about 85% by weight of the composition.

Emollient materials in the form of silicone oils or synthetic esters may be incorporated into the compositions of the present invention. These may be present in amounts ranging from about 0.1 to about 30%, preferably between about 1 and 20% by weight of the composition.

Silicone oils may be divided into the volatile and nonvolatile variety. The term "volatile" as used herein refers to those materials which have a measurable vapor pressure at ambient temperature. Volatile silicone oils are preferably chosen from cyclic or linear polydimethylsiloxanes containing from about 3 to about 9, preferably from about 4 to about 5, silicon atoms.

Linear volatile silicone materials generally have viscosities less than about 5 centistokes at 25°C while cyclic materials typically have viscosities of less than about 10 centistokes. Nonvolatile silicone oils which are suitable as emollients for the compositions of the present invention include polyalkyl siloxanes, polyalkylaryl siloxanes or polyether siloxane copolymers (e.g. di ethicone copolyol). Suitable non-volatile polyalkyl siloxanes include, for example, polydimethyl siloxanes with viscosities ranging from about 5 to about 100,000 centistokes at 25°C. Among the preferred non-volatile emollients which are useful in the present compositions are polydimethyl siloxanes having viscosities from about 10 to about 400 centistokes at 25°C.

Suitable ester emollients include:

(1) alkenyl esters of fatty acids having 10 to 20 carbon atoms, such as methyl myristate, methyl stearate, oleyl myristate, oleyl stearate, or butyl oleate;

(2) ether-esters such as fatty acid esters of ethoxylated fatty alcohols;

(3) polyhydric alcohol esters, such as ethylene glycol mono and di-fatty acid esters, diethylene glycol mono- and di-fatty acid esters, polyethylene glycol (200-6000) mono- and di-fatty acid esters, propylene glycol mono- and di- fatty acid esters, polypropylene glycol 2000 monooleate, polypropylene glycol 2000 monostearate, ethoxylated propylene glycol monostearate, glyceryl mono- and di-fatty acid esters, polyglyceroi poly-fatty esters, ethoxylated glyceryl monostearate, 1,3-butylene glycol monostearate, 1,3-butylene glycol distearate, polyoxyethylene polyol fatty acid ester, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters;

(4) wax esters such as beeswax, spermaceti, myristyl myristate, stearyl stearate;

(5) sterols esters, such as cholesterol fatty acid esters .

The preferred ester emollients are C1-C3 alkyl fatty esters such as methyl stearate, methyl myristate and methyl palmitate. C8-C20 alkyl esters of fatty acids such as cetyl palmitate and myristyl myristate are also particularly preferred.

Humectants of the polyhydric alcohol-type may also be included in the compositions of the present invention. The humectant helps to increase the effectiveness of the emollient, reduces scaling, stimulates removal of built-up scale and generally improves skin feel. Typical polyhydric alcohols include glycerol, polyalkylene glycols and more preferably alkylene polyols and their derivatives, including propylene glycol, dipropylene glycol, polypropylene glycol, polyethylene glycol and derivatives thereof, sorbitol, hydroxypropyl sorbitol, isoprene glycol, hexylene glycol, 1,3-butylene glycol, 1, 2 , 6-hexanetrιol , ethoxylated glycerol, propoxylated glycerol and mixtures thereof. The amount of humectant may range anywhere from about 0.5 to about 30%, preferably between 1 and 15% by weight of the composition . Thickeners/viscosiflers in amounts of up to about 5% by weight of the composition may also be included. The skilled person would appreciate that the precise amount of thickener required may vary depending upon the consistency and thickness of the composition desired. Suitable thickeners include xanthan gum, sodium carboxymethyl cellulose, hydroxyalkyl and alkyl celluloses (particularly hydroxypropyl cellulose) , sclerotium gum and polyacrylamide dispersions in isoparaffin such as those sold by Seppic Inc. under the Sepigel® 305 trademark.

Preservatives may also desirably be incorporated into the cosmetic compositions of the present invention to protect against the growth of potentially harmful microorganisms. Suitable traditional preservatives include alkyl esters of para-hydroxybenzoic acid. Other preservatives which have more recently come into use include hydantom derivatives, propionate salts, and a variety of quaternary ammonium compounds. Cosmetic chemists are familiar with appropriate preservatives and routinely choose them to satisfy the preservative challenge test and to provide product stability. Particularly preferred preservatives are disodium EDTA, phenoxyethanol , methyl paraben, butyl paraben, propyl paraben, lmidazolidinyl urea (commercially available as Germall 1157), sodium dehydroacetate and benzyl alcohol. The preservatives should be selected having regard for the use of the composition and possible incompatibilities between the preservatives and other ingredients m the emulsion. The preservatives are preferably employed in amounts ranging from about 0.01% to about 2% by weight of the composition. Advantageously, compositions of the present invention may contain glycyrrhizinic acid and salts thereof. These may be of the alpha or beta glycyrrhizinic variety. Particularly useful are the alkali metal and ammonium salts such as disodium and dipotassium glycyrrhizinate . Amounts of these substances may range from about 0.0001 to about 3%, preferably from about 0.01 to about 1.0%, optimally from about 0.1 to about 0.5% by weight of the composition.

Colorants and fragrances may also be included in the compositions of the present invention. These may be present in amounts ranging from about 0.05 to about 5%, preferably between about 0.1 and about 3% by weight of the composition.

Compositions of the present invention will have a pH ranging from about 1 to about 6.5, preferably from about 2 to about 6.0, more preferably from about 3 to about 5.5, optimally from about 3.5 to about 4.5.

Except m the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material are to be understood as modified by the word "about".

The following examples will more fully illustrate the embodiments of this invention. All parts, percentages and proportions referred to herein and in the appended claims are by weight unless otherwise illustrated. EXAMPLES 1-8

The following examples are illustrative of vanishing cream formulations according to the present invention.

Vanishing Cream

EXAMPLE 9

A series of stability tests were conducted to establish the performance of fatty acid saccharides as stabilizing agents for low pH vanishing creams. Table I provides formulations of compositions which were comparatively tested. TABLE I

Stability was determined in a 6 months storage stability test. Samples were stored for six months with temperatures alternating from 25°C (room temperature) to 6°C to 45°C and exposed to sunlight. Samples with satisfactory stability within the six month period may normally be expected to be stable for about 2-3 years in the marketplace.

Formulation A employing methyl glucose sesquistearate as a stabilizer provided a stable emulsion without any phase separation. By contrast, replacement with an alkyl polyglucoside such as lauryl polyglucose at 75%, 100% and 125% of the methyl glucose sesquistearate levels (compare formulations B, C and D respectively) resulted m phase instability with at least some water leaving the emulsion upon storage.

The foregoing description and examples illustrate selected embodiments of the present invention. In light thereof variations and modifications will be suggested to one skilled in the art, all of which are within the spirit and purview of this invention.

Claims

1. A cosmetic composition comprising:

(I) from 5 to 50% by weight of a C₁₂-C₂0 fatty acid; (11) from 0.1 to 20% by weight of a C₈-C₂₂ fatty acid substituted sacchaπde; wherein the composition has a pH from about 1 to about 6.5.

2. A composition according to claim 1 wherein the C₁₂-C₂₀ fatty acid is stearic acid.

3. A composition according to claim 1 or claim 2 wherein the C₁₂-C₂0 fatty acid is present in an amount from about 10 to about 25% by weight.

4. A composition according to any one of the preceding claims further comprising an acidic skin benefit agent.

5. A composition according to claim 4 wherein the acidic skin benefit agent is selected from alpha-hydroxy carboxylic acids, beta-hydroxy carboxylic acids or mixtures thereof.

6. A composition according to claim 5 wherein the alpha- hydroxy carboxylic acids are selected from glycolic acid, lactic acid, 2-hydroxyoctanoιc acid or combinations thereof.

7. A composition according to claim 5 or claim 6 wherein the beta-hydroxy carboxylic acid is salicylic acid.

8. A composition according to any one of the preceding claims wherein the pH ranges from 2 to 6.0.

9. A composition according to any one of the preceding claims further comprising from about 0.0001 to about 3% by weight of glycyrrhizinic acid or a salt thereof.

10. A composition according to any one of the preceding claims wherein the fatty acid substituted saccharide is methyl glucose sesquistearate.