SKIN CARE COMPOSITIONS CONTAINING AN ACID AND A RETINOID

Abstract: Oleanolic acid and/or ursolic acid in combination with retinol or retinyl ester substantially inhibits keratinocyte differentiation. The effects of oleanolic acid and/or ursolic acid in combination with retinol or retinyl ester are analogous to treatment with retinoic acid.

Description: SKIN CARE COMPOSITIONS CONTAINING AN ACID AND A RETINOID Field of the Invention The invention relates to skin care compositions containing an acid and a retinoid and to cosmetic methods involving applying such compositions to the skin. Background of the Invention Retinol (vitamin A) is an endogenous compound which occurs naturally in the human body and is essential for normal epithelial cell differentiation. Natural and synthetic vitamin A derivatives have been used extensively in the treatment of a variety of skin disorders and have been used as skin repair or renewal agents. Retinoic acid has been employed to treat a variety of skin conditions, e.g., acne, wrinkles, psoriasis, age spots and discoloration. See e.g., Vahlquist, A. et al., J. Invest. Dermatol., Vol. 94, Holland D.B. and Cunliffe, W.J. (1990), pp. 496-498; Ellis, C. N. et al., "Pharmacology of Retinols in Skin", Vasel, Karger, Vol. 3, (1989), pp. 249-252; Lowe, N.J. et al . , "Pharmacology of Retinols in Skin", Vol. 3, (1989), pp. 240-248; PCT Patent Application No. WO 93/19743. It is believed that the use of retinol or esters of retinol would be preferred over retinoic acid. Retinol is an endogenous compound. Esters of retinol hydrolyze in-vivo to produce retinol. Retinol and retinyi esters are considered safer than retinoic acid. The present invention is based, in part, on the discovery that a combination of retinol or retinyi ester with oleanolic acid and/or ursolic acid results in a synergistic inhibition of keratinocyte differentiation. The effects of oleanolic acid and/or ursolic acid combined with retinol or a retinyi ester were analogous to the effects of retinoic acid. Thus, a mixture of oleanolic acid and/or ursolic acid with retinol or retinyi esters mimics retinoic acid yet is easier and safer to use than retinoic acid. Summary of the Invention The present invention includes, in part, a skin conditioning composition containing: (a) from 0.001% to 10% of a retinoid selected from the group consisting of retinol, retinyi ester, and mixtures thereof; (b) from 0.0001% to 50% of a compound selected from the group consisting of oleanolic acid, ursolic acid and mixtures thereof; and (c) a cosmetically acceptable vehicle. The invention also provides a cosmetic method of conditioning skin comprising topically applying the present composition to the skin. It further provides a cosmetic method mimicking the effect of retinoic acid on skin, comprising topically applying the present composition to the skin. The term "conditioning" as used herein means prevention and treatment of one or more of the following skin conditions: dry skin, photodamaged skin, appearance of wrinkles, age spots, aged skin, acne, psoriasis, atopic dermatosis. The compositions may also be employed to achieve skin lightening, increase stratum corneum flexibility, control sebum excretion and generally increase the quality of skin. The composition may be used to improve skin desquamation and cellular proliferation. Description of the Preferred Embodiment The inventive compositions contain, as a first essential ingredient, a compound selected from the group consisting of retinol, retinyi esters and mixtures thereof. The term "retinol" includes amongst others the following isomers of retinol: all-trans-retinol , 13-cis-retinol , 11- cis-retinol, 9-cis-retinol, 3 , 4-didehydro-retinol . Preferred isomers are all-trans-retinol, 13-cis-retinol, 3 , 4-didehydro- retinol, 9-cis-retinol . Most preferred is all-trans-retinol, due to its wide commercial availability. Retinyi ester is an ester of retinol. The term "retinol' has been defined above. Retinyi esters suitable for use in the present invention are C J -C J ,, esters of retinol, preferably C,-C 2( esters, and most preferably C 2 , C 3 , and C lb esters because they are more commonly available. Examples of retinyi esters include but are not limited to: retinyi palmitate, retinyi formate, retinyi acetate, retinyi propionate, retinyi butyrate, retinyi valerate, retinyi isovalerate, retinyi hexanoate, retinyi heptanoate, retinyi octanoate, retinyi nonanoate, retinyi decanoate, retinyi undecandate, retinyi laurate, retinyi tridecanoate, retinyi myristate, retinyi pentadecanoate, retinyi heptadeconoate, retinyi stearate, retinyi isostearate, retinyi nonadecanoate, retinyi arachidonate, retinyi behenate, retinyi linoleate, retinyi oleate, retinyi lactate, retinyi glycolate, retinyi hydroxy caprylate, retinyi hydroxy laurate, retinyi tartarate. The preferred ester for use in the present invention is selected from retinyi palmitate, retinyi acetate and retinyi propionate, because these are the most commercially available and therefore the cheapest. Retinyi linoleate is also preferred due to its efficacy. The retinoid is employed in the inventive composition in an amount of from 0.001% to 10%, preferably m an amount of from 0.01% to 1%, most preferably in an amount of from 0.01% to 0.5%. The second essential ingredient of the inventive compositions is oleanolic acid, ursolic acid or a combination thereof. The structures of these acids are as follows: Oleanolic Acid Ursolic Acid It should be understood that depending on the pH of the composition, oleanolic acid and/or ursolic acid may be present in the composition as a salt, e.g. alkali or alkaline earth salt. Oleanolic acid and/or ursolic acid is included in the inventive compositions in an amount ranging from 0.0001% to 50%, preferably from 0.01% to 10%, most preferably from 0.1% to 5%. Cosmeticallv Acceptable Vehicle The composition according to the invention also comprises a cosmetically acceptable vehicle to act as a dilutant, dispersant or carrier for the active ingredients in the composition, so as to facilitate their distribution when the composition is applied to the skin. Vehicles other than or in addition to water can include liquid or solid emollients, solvents, humectants, thickeners and powders. An especially preferred nonaqueous carrier is a polydimethyl siloxane and/or a polydimethyl phenyl siloxane. Silicones of this invention may be those with viscosities ranging anywhere from 10 to 10, 000, 000mm 2/ s (centistokes) at 25 ° C. Especially desirable are mixtures of low and high viscosity silicones. These silicones are available from the General Electric Company under trademarks Vicasil, SE and SF and from the Dow Corning Company under the 200 and 550 Series. Amounts of silicone which can be utilized in the compositions of this invention range anywhere from 5% to 95%, preferably from 25% to 90% by weight of the composition. The cosmetically acceptable vehicle will usually form from 5% to 99.9%, preferably from 25% to 80% by weight of the composition, and can, m the absence of other cosmetic adjuncts, form the balance of the composition. Preferably, the vehicle is at least 50 wt.%, more preferably at least 80 wt . % water , by weight of the vehicle. Preferably, water comprises at least 50 wt.% of the inventive composition, most preferably from 60 to 80 wt.%, by weight of the composition. Optional Skin Benefit Materials and Cosmetic Adjuncts An oil or oily material may be present, together with an emulsifier to provide either a water-in-oil emulsion or an oil-in-water emulsion, depending largely on the average hydrophilic-lipophil c balance (HLB) of the emulsifier employed. The inventive compositions preferably include sunscreens. Sunscreens include those materials commonly employed to block ultraviolet light. Illustrative compounds are the derivatives of PABA, cinnamate and salicylate. For example, octyl methoxycmnamate and 2-hydroxy-4-methoxy benzophenone (also known as oxybenzone) can be used. Octyl methoxycinnamate and 2-hydroxy-4-methoxy benzophenone are commercially available under the trademarks, Parsol MCX and Benzophenone-3 , respectively. The exact amount of sunscreen employed in the emulsions can vary depending upon the degree of protection desired from the sun's UV radiation. Another preferred optional ingredient is selected from essential fatty acids (EFAs) , i.e., those fatty acids which are essential for the plasma membrane formation of all cells, in keratinocytes EFA deficiency makes cells hyperproliferative. Supplementation of EFA corrects this. EFAs also enhance lipid biosynthesis of epidermis and provide lipids for the barrier formation of the epidermis. The essential fatty acids are preferably chosen from linoleic acid, γ-linolenic acid, homo-γ-linolenic acid, columbinic acid, eicosa- (n-6, 9, 13 ) -trienoic acid, arachidonic acid, α-linolenic acid, timnodonic acid, hexaenoic acid and mixtures thereof. Yet another preferred optional ingredient is selected from azoles, e.g., climbazole, bifonazole, clotrimazole, ketoconazole, miconazole, econazole, itraconazole, fluconazole, terconazole, butoconazole, sulconazole, lionazole and mixtures thereof. The azole may be included in the inventive compositions in an amount of from 0.001 to 50 wt. %, preferably from 0.001 to 10 wt.%, most preferably from 0.1 to 5%. Emollients are often incorporated into cosmetic compositions of the present invention. Levels of such emollients may range from 0.5% to 50%, preferably between 5% and 30% by weight of the total composition. Emollients may be classified under such general chemical categories as esters, fatty acids and alcohols, polyols and hydrocarbons. Esters may be mono- or di-esters. Acceptable examples of fatty di-esters include dibutyl adipate, diethyl sebacate, diisopropyl dimerate, and dioctyl succinate. Acceptable branched chain fatty esters include 2-ethyl-hexyl myristate, isopropyl stearate and isostearyl palmitate. Acceptable tribasic acid esters include triisopropyl trilinoleate and trilauryl citrate. Acceptable straight chain fatty esters include lauryl palmitate, myristyl lactate, oleyl eurcate and stearyl oleate. Preferred esters include coco- caprylate/caprate (a blend of coco-caprylate and coco- caprate) , propylene glycol myristyl ether acetate, diisopropyl adipate and cetyl octanoate. Suitable fatty alcohols and acids include those compounds having from 10 to 20 carbon atoms. Especially preferred are such compounds such as cetyl, myristyl, palmitic and stearyl alcohols and acids. Among the polyols which may serve as emollients are linear and branched chain alkyl polyhydroxyl compounds. For example, propylene glycol, sorbitol and glycerin are preferred. Also useful may be polymeric polyols such as poly-propylene glycol and polyethylene glycol . Butylene and propylene glycol are also especially preferred as penetration enhancers. Exemplary hydrocarbons which may serve as emollients are those having hydrocarbon chains anywhere from 12 to 30 carbon atoms. Specific examples include mineral oil, petroleum jelly, squalene and isoparaffins. Another category of functional ingredients within the cosmetic compositions of the present invention are thickeners. A thickener will usually be present in amounts anywhere from 0.1 to 20% by weight, preferably from 0.5% to 10% by weight of the composition. Exemplary thickeners are cross-linked polyacrylate materials available under the trademark Carbopol from the B.F. Goodrich Company. Gums may be employed such as xanthan, carrageenan, gelatin, karaya, pectin and locust bean gum. Under certain circumstances the thickening function may be accomplished by a material also serving as a silicone or emollient. For instance, silicone gums with viscosity in excess of 10 centistokes and esters such as glyceroi stearate have dual functionality. Powders may be incorporated into the cosmetic composition of the invention. These powders include chalk, talc, Fullers earth, kaolin, starch, smectite clays, chemically modified magnesium aluminum silicate, organically modified montmorillonite clay, hydrated aluminum silicate, fumed silica, aluminum starch octenyl succinate and mixtures thereof . Other adjunct minor components may also be incorporated into the cosmetic compositions. These ingredients may include coloring agents, opacifiers and perfumes. Amounts of these other adjunct minor components may range anywhere from 0.001% up to 20% by weight of the composition. Use of the Composition The composition according to the invention is intended primarily as a product for topical application to human skin, especially as an agent for conditioning and smoothening the skin, and preventing or reducing the appearance of wrinkled or aged skin. In use, a small quantity of the composition, for example from 1 to 100ml, is applied to exposed areas of the skin, from a suitable container or applicator and, if necessary, it is then spread over and/or rubbed into the skin using the hand or fingers or a suitable device. Product Form and Packaging The topical skin treatment composition of the invention can suitably be formulated as a lotion, a cream or a gel. The composition can be packaged in a suitable container to suit its viscosity and intended use by the consumer. For example, a lotion or cream can be packaged in a bottle or a roll-ball applicator, or a propellant-driven aerosol device or a container fitted with a pump suitable for finger operation. When the composition is a cream, it can simply be stored in a non-deformable bottle or squeeze container, such as a tube or a lidded jar. The composition may also be included in capsules such as those described in U.S. Patent 5,063,057. The invention accordingly also provides a closed container containing a cosmetically acceptable composition as herein defined. The following specific examples further illustrate the invention. Retinoids used in the examples were obtained from Sigma. Ursolic and oleanolic acids were obtained from Aldrich. MATERIALS AND METHODS ςell C lture; Human keratinocytes, isolated from neonatal foreskin by trypsin treatment were grown in Dulbecco Modification Eagle (D E) Hams F12 (1:1) medium/10% fetal calf serum in the presence of irradiated 3T3 mouse fibroblasts for establishing dividing keratinocyte colonies. Cells were grown under the above condition until their second passage and kept frozen for future use. Frozen second passage keratinocytes were thawed and plated into the above medium and grown for five days before they were switched to a serum-free MCDB 153-based medium keratinocyte growth medium (KGM) from Clonetics Corporation, San Diego, CA, containing 0.15 mM Ca, or keratinocyte serum-free media (KSFM) from GIBCO containing 0.09 mM Ca) . On day 7, when the cells were 80-90% confluent, they were trypsinized and plated in the serum- free medium for the various experiments. TRANSGLUTAMINASE ASSAY Transglutaminase Assay and Keratinocyte Differentiation During the process of terminal differentiation in the epidermis, a 15nm thick layer of protein, known as the cornified envelope (CE) is formed on the inner surface of the cell periphery. The CE is composed of numerous distinct proteins which have been cross-linked together by the formation of if- (γ-glutamyl) lysine isodipeptide bonds catalyzed by the action of at least two different transglutaminases (TGases) expressed in the epidermis. Transglutaminase I (TGase I) is expressed in abundance in the differentiated layers of the epidermis, especially the granular layer, but is absent m the undifferentiated basal epidermis. Thus TGase I is a useful marker of epidermal keratinocyte differentiation with high TGase I levels indicating a more differentiated state. An ELISA based TGase I assay, using a TGase I antibody, was used to assess the state of differentiation of the cultured keratinocytes in the examples that follow. For Example 1, the following procedure was used: Keratinocytes (cultured as described above) were plated m 96 well plates at a density of 3,000 cells per well in 200 μl media. After incubation for four days the media was changed to media containing test compounds (six replicates pei test). The cells were cultured for a further 72 hours after which time the media was aspirated and the plates stored at -70 C. Plates were removed from the freezer, and the cells washed with PBS. 100 μl sterile water was added and the cells were freeze fractured by freezing at -70 C then thawing The cells were incubated for one hour at room temperature (R/T) with PBS/ 3% BSA (wash buffer, bovine serum albumin) , then rinsed with a fresh aliquot of wash buffer. Cells were incubated with 50 μl of primary antibodies monoclonal anti-human transglutaminase mouse antibody (IgG) obtained from Biomedical Industries diluted 1:2,000 in wash buffer for one hour, 37 ° C then rinsed two times with wash buffer. Cells were then incubated with 50 μl of secondary antibody (Fab fragment, peroxidase conjugated anti-mouse IgG obtaining from Amersham) diluted 1:4,000 in wash buffer for one hour at 37 C, then rinsed two times with wash buffer. Cells were incubated with substrate solution (4 mg o-phenylene diamine and 3.3 μl 30% H 2 0 2 in 10ml 0.1M citrate buffer pH 5.0) for five minutes, R/T, m darkness (under aluminum foil). The reaction was stopped by the addition of 50 μl 4N H 2 S0 4 . The absorbance of samples was read at 492nm in the plate reader. Out of the six replicates, four were treated with both antibodies, two were treated only with the secondary antibody (i.e., to determine background binding of enzyme conjugated Ab) . TGase levels were determined by subtracting background from the readings from each treatment and determining mean ± s.d. for the replicates exposed to both antibodies. For Example 2, the following procedure was used: Keratinocytes (cultured as described above) were plated m 96 well plates at a density of 3,000 cells per well in 200μl of cell culture media. After incubation for four days, the media was changed to media containing test compounds (six replicates per test) . The cells were cultured for a further 72 hours after which time the media was aspirated and the plates stored at -70 ° C. After the plates were removed from the freezer, the cells were further freezed fractured by freezing and thawing and then washed 3x with PBS. The cells were incubated for one hour at room temperature (R/T) with TBS/5% BSA buffer. Cells were then incubated with 100:1 of monoclonal anti-human transglutaminase (IgG) mouse antibody (primary antibody) obtained from Biomedical Technologies Inc. diluted 1:2000 in TBS/1% BSA buffer for two hours at 37 ° C, and then rinsed six times with wash buffer (TBS/1% BSA/0.05% Tween-20) Cells were next incubated with lOOμl of Fab fragment, peroxidase conjugated anti-mouse IgG antibody (secondary antibody) from Amersham diluted 1:4,000 in wash buffer for two hours at 37 ° C and then rinsed three times with wash buffer and three times with PBS. Cells were incubated with substrate solution (4mg o-phenylene diamine and 3.3μl 30% H 2 0 2 in lOmL 0.1M citrate buffer, pH 5.0) for five minutes at R/T and m darkness (under aluminum foil) . The reaction was stopped by the addition of 50μl 4N H,SO.. The absorbance of samples was read at 492nm m the plate reader. Out of the six replicates, four were treated with both antibodies, two were treated only with the secondary antibody (i.e., to determine the background binding of the enzyme conjugated antibody) . Transglutaminase I levels were determined by subtracted background from the readings from each treatment and determining the mean ± s.d. for the replicates exposed to both antibodies. DNA Assay The level of Tgase I detected after treatment of the cells could be influenced by cell number, i.e., the greater the number of cells the greater the level of Tgase I detected. The level of Tgase I was normalized to DNA content of the cells in the same well thus eliminating variation due to differences in cell number. DNA quantitation is a particularly useful indicator of cell number, including keratinocyte cell number, because each cell has to all intents and purposes an identical genome and therefore an identical quantity of DNA. The total DNA content of a well of cells therefore is directly proportional to the cell number in that well. Quantitation of DNA was used to normalize the TGase data to cell number. Keratinocytes were plated in 96 well plates at a density of 3,000 cells per well in 200μl media. After incubation for four days the media was changed for media containing test compounds (6 replicates per test) . The cells were cultured for a further 72 hours after which time the media was aspirated and the plates stored for at least 1.5 hours at - 70 ° C. Plates were removed from the freezer and thawed for 30 minutes. lOOμl/well of Hoechst dye (lμg/ml final concentration) was added and this was incubated for 15 minutes, covered and then read in a fluorimeter (ex. 360nm and em. 460nm) . The dye solution was removed and the wells were rinsed with PBS in preparation for the TGase assay. EXAMPLE 1 Retinoic acid is more effective than retinol at altering keratinocyte differentiation state The effect on Transglutaminase levels normalized to DNA content of the cells after addition of retinoic acid (RA) and retinol (ROH) was examined and the results are shown in Table 1. TABLE 1 0Ϊ c CD (A H H C H m W X m m a c I r m t n All concentrations of retinoic acid tested, i.e., 2.5x10 " M, 2.5x10 " ^ and 2.5x10 "9 M decreased keratinocyte differentiation over the ethanol control and did so to a significantly greater extent than each of the corresponding 2.5x10 "7 M, 2.5xl0 "8 M and 2.5xlO "9 M retinol treatments. The decrease in transglutaminase level was dose dependent for both retinoic acid and retinol. This is consistent with retinoic acid having a greater inhibitory effect on epithelial differentiation than retinol. EXAMPLE 2 Oleanolic Acid and Retinol Svnergisticallv Inhibit Keratinocyte Differentiation The effect on Tgase I levels normalised to DNA content of the cells was examined in response to a 72 hour treatment with the test compounds. The results are shown in Table 2. TABLE 2 Effect of Retinol and Oleanolic Acid on Keratinocyte TQase/DNA n c CD CO H H C m O x rn m 33 c r- m r 2.5x10 7 M retinoic acid was very effective at repressing keratinocyte Tgase I levels (to 44% of control level) 2.5x10 7 M retinol was less effective than retinoic acid and 10 δ M oleanolic acid had only a slight inhibitory effect on the keratinocyte Tgase I level when used alone. However, 2.5x 10 7 M retinol + 10 *6 M oleanolic acid repressed keratinocyte Tgase I to 66% of control levels. Oleanolic acid and retinol therefore act synergistically to repress keratinocyte differentiation in an analogous manner to the effect of retinoic acid. In Examples 1-2, retinoic acid was used as positive control and reference compound against which the other compounds under analysis were compared. Retinoic acid, m a dose dependent manner decreased transglutaminase I levels m skin keratinocytes. In other words retinoic acid decreased keratinocyte differentiation. Retinol was significantly less effective than retinoic acid at inhibiting keratinocyte differentiation. The unexpected result of this study however was that the effect of retinol on cultured keratinocytes can be enhanced to levels approaching those of retinoic acid by combining retinol with oleanolic acid. This effect was not only greater than the effect of either retinol or oleanolic acid itself but the two ingredients acted in synergy with each other to promote a retinoic acid response on the keratinocytes . Examples 3-8 illustrate topical compositions according to the present invention. The compositions can be processed in conventional manner. They are suitable for cosmetic use In particular the compositions are suitable for application to wrinkled, rough, dry, flaky, aged and/or UV-da aged skin to improve the appearance and the feel thereof as well as for application to healthy skin to prevent or retard deterioration thereof. EXAMPLE 3 This example illustrates a high internal phase water-m-oil emulsion incorporating the inventive composition. Brij 92 is polyoxyethylene (2) oleyl ether EXAMPLE 4 This example illustrates an oil-m-water cream incorporating the inventive composition. * Brij 56 is cetyl alcohol POE (10] Alfol 16RD is cetyl alcohol EXAMPLE 5 This example illustrates an alcoholic lotion incorporating the composition according to the invention. EXAMPLE ξ This example illustrates another alcoholic lotion containing the inventive composition. EXAMPLE 7 This example illustrates a suncare cream incorporating the composition of the invention: EXAMPLE 8 This example illustrates a non-aqueous skin care composition incorporating the inventive combination. 1 A dimethyl silicone polymer having a molecular weight of at least 50,000 and a viscosity of at least 10,000 centistokes at 25 ° C, available from GEC 2 Dimethyl siloxane cyclic pentamer, available from Dow Corning Corp. 3 Dimethyl siloxane tetramer, available from Dow Corning Corp.

Claims: CLAIMS 1. A skin conditioning composition comprising (a) from 0.001% to 10% of a retinoid selected from the group consisting of retinol, retinyi ester and mixtures thereof; (b) from 0.0001% to 50% of an acid selected from the group consisting of oleanolic acid, ursolic acid, and mixtures thereof; and (c) a cosmetically acceptable vehicle. 2. The composition of claim 1 wherein the retinyi ester is selected from the group consisting of retinyi palmitate, retinyi acetate, retinyi propionate, retinyi linoleate and mixtures thereof. 3. The composition of claim 1 wherein ingredient (a) is retinol. 4. The composition of claim 1 wherein ingredient (a) is a retinyi ester. 5. A cosmetic method of conditioning skin the method comprising applying topically to skin a composition according to any one of claims 1 - 4. 6. A cosmetic method of mimicking the effect on skin of retinoic acid, the method comprising applying to the skin a composition according to any one of claims 1-4.

Inventors: GRANGER STEWART PATON, SCOTT IAN RICHARD, GRANGER, STEWART, PATON, SCOTT, IAN, RICHARD
Applicants: UNILEVER NV, UNILEVER PLC
Application year: 1997
Main classification: A61K7
IPC codes: A61K8, A61K31, A61P17, A61Q17, A61Q19