Compositions containing retinoic acids and tocopherol

Abstract: Compositions of retinoic acids and tocopherols may be applied topically without producing retinoic acid-induced skin irritation.

Description: Retinoic acids such as 13-cis-retinoic acid and all-trans-retinoic acid are known to have beneficial dermatological effects, i.e. on human skin, and may be applied to retard the effects of photoaging on skin, or to combat acne, or in general to improve skin quality. The document, GB-A-1466062 discloses cosmetic preparations containing 0.001% to 0.1% by weight of retinoic acid or a salt or an ester thereof and alpha tocopherol. However, repeated topical application of retinoic acids to human skin for these dermatological purposes may initially cause transient skin irritation (dermatitis) which may be characterized by erythema, scaling, pruritus, and sensations similar to sunburn. Such results are also observed in animals after repeated topical dosing with retinoic acids. The inflammatory component of retinoic acid induced skin irritation in animals can be demonstrated histologically by an influx of inflammatory cells into the skin. In mice, for example, topical retinoic acid induced skin irritation is characterized by an inflammatory response and, after repeated topical applications, epidermal hyperproliferation. The effect can be quantified biochemically from measurement of increased myeloperoxidase (MPO) activity in skin biopsy punches (Bradley et a., J. Invest. Dermatol. 1982; 78: 206-209). In accordance with the present invention it has been found that the problem of retinoic acid induced dermatitis resulting from topical retinoic acid application for dermatological effects can be overcome by adding a tocopherol such as alpha tocopherol to the topical composition.. The subject invention is directed to a liquid composition suitable for topical administration which comprises about 0.05 to about 0.2% by weight of 13-cis retinoic acid and about 0.005 to about 5.0% by weight of alpha tocopherol per volume of said liquid composition. In particular, the alpha tocopherol may be present in a range of about 0.01% to about 5.0% by weight per volume. The liquid compositions can be applied in accordance with this invention to human skin in conventional topical compositions. The dermatological effects of retinoic acids are well known. These effects make retinoic acids useful in a range of applications. For example, retinoic acids may be used to treat dermatological disorders such as acne, photodamage (i.e., wrinkling) and epithelial carcinomas which can be reduced in size by treatment. These topical compositions are in the form of liquid compositions suitable for topical administration (including for example creams, gels, ointments, microemulsions, shampoos, and solutions). These liquid compositions may be applied to the skin of the body, in particular face, legs, arms and hands. They may be administered in any conventional topical preparations, i.e., in combination with any suitable conventional carrier useful for topical administration. Such topical compositions include cream, ointment, soap, solutions, lotions, emulsions, shampoo and any other conventional topical preparations. In formulating the preparations, any conventional non-toxic dermatologically acceptable base or carrier in which these compositions are stable is acceptable. Preferred compositions may contain conventional cosmetically active ingredients. Examples of conventional cosmetically active materials are sunscreens, penetration enhancers, moisturizers, surfactants, emollients, colorants, conditioners, bacteriocides, astringents, detergents and other such materials. Any conventional sunscreen may be included in the claimed composition. These topical compositions can contain any conventional excipients and additives commonly used in preparing skin compositions. Among the conventional additives or excipients are preservatives, thickeners, perfumes and the like. In addition, conventional anti-oxidants such as butylated hydroxy anisoles (BHA), ascorbyl palmitate, propyl gallate, citric acid, butylated hydroxytoluene (BHT), ethoxyquin, and the like can be incorporated into these compositions. These compositions may contain thickening agents, solubilizers, humectants, emulsifiers and viscosity stabilizers, any of which are well known in the art. In addition, these compositions can contain flavoring, perfuming, or coloring agents conventionally used. The topical compositions should be applied to the skin with a frequency to be determined for an individual patient. In general, the particular regimen for application will depend on the age, weight, and skin condition of the individual. However, an exemplary regimen for retinoic acid application to reverse sun damage and reduce wrinkling is at least one application to the skin at least 2 or 3 times weekly for at least 5 months, and thereafter as needed to maintain skin elasticity. For acne treatment, an exemplary regimen is one or more applications daily for about four to six weeks. This invention is further illustrated in the following examples. Example 1 Example 1 demonstrates that skin irritation caused by topical application of retinoic acid can be reduced if the retinoic acid is applied with alpha-tocopherol. Skin irritation is determined from the amount of inflammation developed in the area of application, specifically the ear. The amount of inflammation is related to the increase in the number of inflammatory cells (neutrophils) in ear tissues caused by retinoic acid application. Increase in neutrophils is directly proportional to MPO activity (MPO is a neutrophil marker enzyme), which activity is quantified colorimetrically by adding substrate and measuring optical density resulting from the MPO reacting on the substrate. Increased ear weight due to inflammation is another measure of the amount of inflammation caused by retinoic acid application. Male CD-1 mice (5 weeks old) were dosed topically on the dorsal side of the right ear daily for eight (8) days with 25µl of an acetone solution containing both 0.08% (20 µg/25 µl) 13-cis-retinoic acid and various doses of alpha tocopherol (Vitamin E), ranging from 0.01% to 5.0% (2.5 µg to 1.2 mg). Eight animals per group were used. Control groups were treated either with a solution of 0.08% 13-cis-retinoic acid alone or with the solvent (acetone). On day nine (9) the animals were sacrificed by CO 2 inhalation and biopsy punches (6mm diameter) were removed from the treated ears. The biopsy punches were weighed, homogenized, and the homogenate was assayed for MPO activity, according to the method of Bradley, et al. I.c. which was adapted to 96 well microtiter plates. MPO activity was determined by measuring the change in optical density of the reaction mixture at 450 nm in a 96 well plate reader (SLT Lab instruments) over a period of two minutes. The data are expressed as percent inhibition of alpha tocopherol (Vitamin E) treated groups relative to the control groups according to the formula : % inhibition = Δ O.D. RA - Δ O.D. (RA + E) Δ O.D. RA - Δ O.D. control x 100 Topical application of 13-cis-retinoic acid for eight (8) days to mouse ears resulted in a dose related increase in infiltration of polymorphonuclear neutrophils, as indicated by the increase in MPO activity. Ear wet weight was also increased in a dosed-related manner and this increase was partially due to ear inflammation and epidermal hyperproliferation in response to the retinoic acid. Alphatocopherol, at concentrations from 0.01% to 5.0%, inhibited the retinoic acid-induced increase in MPO activity (neutrophil inflitration) in a dose related manner. Maximum inhibition (70%) of 13-cis-retinoic acid-induced neutrophil infiltration was obtained at an alpha-tocopherol concentration of 5.0%. These data clearly demonstrate that topical alpha tocopherol (optimum doses) can ameliorate the inflammatory component induced by repeated topical application of 13-cis-retinoic acid. Example 2 The liquid compositions described herein can be provided for topical application in creams, lotions, shampoos, and any other topical formulation. The percentages given in these examples are percent by weight based on the total volume of the liquid composition. Specific formulations are described below. However, any conventional formulation can be used for the claimed composition. a. Liposomal Formulations Ingredient % by Weight Isotretinoin 0.050 - 1.000 Vitamin E 0.005 - 5.000 L-α-Dimyristyl Phosphatidyl Choline 0.062 Cholesterol 0.062 T-Butyl Alcohol 31.089 Lactose 6.000 Purified Water q.s. to 100.000 b. Water in Oil Cream Ingredient % by Weight Isotretinoin 0.050 - 1.000 Vitamin E 0.005 - 5.000 Propylene Glycol Dicaprylate/Dicaprate and Stearalkonium Bentonite (and) Propylene Carbonate 20.000 Caprylic/Capric Triglyceride 20.000 Isostearyl Diglyceryl Succinate 5.000 Purified Water q.s. to 100.000 c. Hair Conditioning Gel Ingredient % by Weight Isotretinoin 0.050 - 1.000 Vitamin E 0.005 - 5.000 PEG-7-Glyceryl Cocoate 10.000 Ethanol, Anhydrous 24.000 Methyl pyrol 5.000 Dimyristyl Phosphatidyl Choline 0.030 Sodium Ascorbate 0.030 Citric Acid 0.100 Carbomer 940 0.500 B-Alanine 0.500 Purified Water q.s. to 100.000 d. Oil in Water Cream Ingredient % by Weight Isotretinoin 0.05 - 1.00 Vitamin E 0.005 - 5.00 Propylene Glycol Dicaprylate/Dicaprate 8.95 Stearyl Alcohol 0.75 Glyceryl Stearate 4.00 Ceteareth-12 0.50 Ceteareth-20 0.50 Propylparaben 0.10 Methylparaben 0.15 Disodium Edetate 0.03 Glycerin 5.00 Purified Water q.s. to 100.000 e. Cream (Anhydrous) Ingredient % by Weight Isotretinoin 0.05 - 1.00 Vitamin E 0.005 - 5.00 Caprylic/Capric/Stearic Triglyceride 29.00 Glyceryl Cocoate (and) Ceteareth-25 43.00 Propylene Glycol Dicaprylate/Dicaprate 8.95 Mineral Oil q.s. to 100.000 f. Oil in Water Microemulsion Ingredient % by Weight Isotretinoin 0.05 - 1.00 Vitamin E 0.005 - 5.00 DEA-Oleth-3 Phosphate 8.95 Oleth-20 1.00 Oleth-10 15.00 Mineral Oil 4.00 Propylene Glycol Dicaprylate/Dicaprate 8.00 BHT 0.03 Hexetidine 0.10 Citric Acid 0.05 Sodium Ascorbate 0.10 Sorbic Acid 0.10 Glycerin 5.00 Purified Water q.s. to 100.000 g. Topical Solution Ingredient % by Weight Isotretinoin 0.050 - 1.000 Vitamin E 0.005 - 5.000 PEG-7-Glyceryl Cocoate 10.000 Ethanol, Anhydrous 25.000 Purified Water q.s. to 100.000

Claims: A liquid composition for topical administration which comprises 0.05% to 0.2% by weight of 13-cis retinoic acid and 0.005% to 5.0% by weight alpha tocopherol per volume of said liquid composition. A liquid composition of claim 1 which comprises 0.01% to 5.0% alpha tocopherol by weight per volume of said liquid composition.

Inventors: FIEDLER NAGY CHRISTA, QUICK TIMOTHY WARINGTON, SHAPIRO STANLEY SEYMOUR, FIEDLER NAGY, CHRISTA, QUICK, TIMOTHY WARINGTON, SHAPIRO, STANLEY SEYMOUR
Applicants: HOFFMANN LA ROCHE, F. HOFFMANN-LA ROCHE AG
Application year: 1993
Main classification: A61K31
IPC codes: A61Q5, A61K8, A61K31, A61Q19, A61P43, A61P3, A61P17