WO2001070187A1

WO2001070187A1 - LOW pH HIGH FATTY ACID VANISHING CREAM

Info

Publication number: WO2001070187A1
Application number: PCT/EP2001/002343
Authority: WO
Inventors: Dwiwahyu Haryo Suryo; Sandyarani Noerlan
Original assignee: Hindustan Lever Ltd; Unilever NV
Current assignee: Hindustan Unilever Ltd; Unilever NV
Priority date: 2000-03-21
Filing date: 2001-03-01
Publication date: 2001-09-27
Anticipated expiration: 2002-09-21
Also published as: AU2001256179A1; GB0006865D0; ZA200206536B

Abstract

Cosmetic vanishing cream compositions are disclosed based upon relatively high concentrations of fatty acid, especially stearic acid, and an acidic skin benefit agent, with the composition having a pH from 1 to less than 5. Particularly preferred as the acidic skin benefit agent are the alpha- and beta- hydroxy carboxylic acids, especially combinations of these substances.

Description

LOW pH HIGH FATTY ACID VANISHING CREAM

The present invention relates to a cosmetic vanishing cream with enhanced skin benefit properties.

Vanishing creams are popular around the world because they spread easily on 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 glanαs. Moreover, these creams counteract skin dryness to alleviate flaking, cracking and roughness.

The creams are formulated with high levels of stearic acid suspended in water by an emulsifying agent. Typically the emulsifying agent is a potassium or sodium soap formed by the in 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 al . ) discloses vanishing creams which are formulated to include alkali or alkaline earth metal salts of alpha-hydroxy carboxylic acids m order to achieve skin lightening properties. The disclosure describes the new products as having pH above 5. Care was taken in this prior art not to incorporate acid versions of the alpha-hydroxy carboxylic acids into the formulation. 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 in combination with salts of glycyrrhizinic acid, alpha- bisabolol and anti-microbial agents including triclosan.

Accordingly, the present invention aims to provide a vanishing cream having a relatively high level of stearic acid and a skin benefit agent which can enhance the performance of the formulation.

The present invention also aims to provide a vanishing cream with high levels of stearic acid and skin benefit agents, wherein the cream improves moistuπzation, enhanced removal of facial oils, reduction in irritation and generally provides an overall smoother, softer skin.

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:

(l) from 5 to 50° by weight of a C₁₂-C₂₀ fatty acid; (11) from 0.01 to 15° by weight of an acidic skin benefit agent; and wherein the composition has a pH from 1 to less than 5.

In addition, a method is provided for reducing facial inflammation and pimples by applying the above-noted cosmetic composition to the face.

The applicants have surprisingly found that cosmetic vanishing creams which are formulated to have a pH of less than 5, can stably deliver acidic skin benefit agents thereby resulting in compositions which are effective at reducing, or at least minimizing facial pimple formations. Vanishing creams of the present invention which have a high fatty acid content (over 5% of, for example stearic 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 matte finish. Addition of the 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 vanishing cream compositions of the present invention is a Cι₂-C₂o fatty acid, preferably, stearic acid. The fatty acid will be present in amounts ranging from 5 to 50%, preferably from 7 to 40%, more preferably from 10 to 25%, optimally from 12 to 20% by weight of the composition.

A second component of vanishing cream compositions of the present invention is an acidic skin benefit agent, such as alpha- and beta-hydroxycarboxylic acids. A suitable beta- hydroxycarboxylic acid 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 nonisomeπc, 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-hydroxypropanoιc acid (methyllactic acid) ; 2-hydroxybutanoιc acid; 2- hydroxypentanoic acid; 2-hydroxyhexanoιc acid; 2- hydroxyheptanoic 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-hydroxyhexadecanoιc acid (alpha- hydroxypaimitic acid); 2-hydroxyoctadecanoιc acid (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-hydroxyetTianoιc acid (atrolactic acid); 2- ( ' -hydroxyphenyl) 2-hydroxyethanoιc acid; 2- ( ' -chlorophenyl) , 2-hydroxyethanoιc acid; 2-(3'- hydroxy-4 ' -methoxyphenyl) 2-hydroxyethanoιc acid; 2-(4'- hydroxy-3' -methoxyphenyl ) 2-hydroxyethanoιc acid; 3'-(2- hydroxyphenyl) 2-hydroxypropanoιc acid; 3- ( 4 ' -hydroxyphenyl) 2-hydroxypropanoιc acid; and 2- ( 3' , 4 ' -dihydroxyphenyl ) 2- hydroxyethanoic acid.

The most preferred alpha-hydroxy carboxylic acids are glycolic acid, lactic acid or 2-hydroxyoctanoιc acid, and mixture thereof. The alpha-hydroxy alkanoic acids may be present in amounts ranging 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 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 can 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, gmko, tomato, blueberry, cowpea or grape extracts.

Other suitable herbal extracts include ivy horse chestnut, centella asiatica, rosmarinic acid, seπcoside, ruscogenm, escin, escolm, betulinic acid, catechm and derivatives thereof. These may be present in amounts 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 m compositions of the present invention. Typically the anti-microbial agents are selected from triclosan, tπcarbanilide, 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 pyridmethione, zinc sulphate, zinc chloride, zinc phenolsulphonate, aluminum chloride, aluminum sulphate and aluminum chlorhydrate. Amounts of the anti-microbial age t may range 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 nave 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. dimethicone copolyol). Suitable non-volatile polyalkyl siloxanes include, for example, polydimethyl siloxanes with viscosities of from about 5 to about 100,000 centistokes at 25°C. Among the preferred nonvolatile emollients which are useful in the present compositions are the 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, and 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, polyethylenen 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, polyglycerol 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 this 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-hexanetriol, 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 up to about 5% by weight of the composition may also be included. The skilled person would appreciated that the precise amount of thickener required may vary depending upon the consistency and thickness of the composition which is desired. Exemplary thickeners are xanthan gum, sodium carboxymethyl cellulose, hydroxyalkyl and alkyl celluloses (particularly hydroxypropyl cellulose) , sclerotium gum and polyacrylamide dispersions in isoparaffm such as those sold by Seppic Inc. under the Sepigel® 305 trademark.

Preservatives may also desirably be incorporated into the cosmetic compositions of this 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 hydantoin 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, lmidazolidmyl 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. Preservatives are preferably employed m 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. ϊhese 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 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 less than 5, preferably from 2 to 4.8, more preferably from 3 to 4.5, optimally from 3.5 to 4.2.

Except in 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 clinical trial was conducted to evaluate the efficacy against facial pimples and inflammation. The study was conducted in collaboration with the Dermatology Department, Faculty of Medicine, University of Gadjah Mada, Jogjakarta. The method was a randomized, double blind, monadic, vehicle controlled, 12 week use test of various prototype moisturizer formulations on the face. Subjects were required to come to the test site for a prescreen visit to determine if they have a mild to moderate degree of comedonal and papulopustular acne vulgaris according to 1990 American Academy of Dermatology Grading. The selected subjects were required to make six additional visits to the test site over a twelve-week period. At baseline (week 0), week 1, 2, 4, 8 and 12, lesion counts, erythema, dryness measurements by expert assessors (dermatologist^) and self- assessment on sensory has been conducted. Subjects were asked to wash their face with soap and apply the test products at home, twice daily (morning and evening) and maintain a product use diary. Five cells with 60 females (aged 16-26 years old) per cell were randomly assigned to treatment groups. Four of the five groups were treated with experimental formulas containing test active ingredients. The fifth group received a cream base placebo. The active ingredients were formulated in a composition essentially equivalent to that described in Example 1, except that each of the four test products contained different amounts of the actives as indicated in Table I below.

TABLE I

significantly different from placebo at p < 0.05

* * * ISA = 1% salicylic acid 2SA = 2% salicylic acid 1LA = 1% lactic acid TCN = 0.2% Triclosan It is evident from these results that the low pH vanishing cream was able to deliver low pH skin benefiting agents such as the hydroxy carboxylic acids in a very effective manner. Inflammation was substantially reduced, the number of lesions were substantially reduced and hyper-pigmentation was significantly inhibited.

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 0.01 to 15% by weight of an acidic skin benefit agent; wherein the composition has a pH from 1 to less than 5.

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

3. A composition according to claim 1 or claim 2 wherein the 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 wherein the acidic skin benefit agent is selected from alpha-hydroxy carboxylic acids, beta-hydroxy carboxylic acids and mixtures thereof.

5. A composition according to claim 4 wherein the alpha- hydroxy carboxylic acids are selected from glycolic acid, lactic acid, 2-hydroxyoctanoιc acid and combinations thereof.

6. A composition according to claim 4 or claim 5 wherein the beta-hydroxy carboxylic acid is salicylic acid.

7. A composition according to any one of the preceding claims wherein the pH ranges from 2 to 4.8.

8. 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 salt thereof.