Process of making and using composition containing oxidation-sensitive hydrophilic active principle and maleic anhydride copolymer

Abstract

The invention relates to the use of a composition for, e.g., promoting the synthesis of the epidermal ceramides and/or for improving the barrier function of the skin, the composition containing at least one oxidation-sensitive hydrophilic active principle selected from the group consisting of ascorbic acid and its compounds and at least one maleic anhydride copolymer. The invention also relates to a cosmetic process for moisturizing the skin comprising the application to the skin of a composition as defined above.

1 . A method for promoting the synthesis of the epidermal ceramides and/or for improving the barrier function of the skin, or for maintaining and/or improving the radiance of the complexion, or for preventing and/or combating roughness of the skin, or for moisturizing or treating dry skin, comprising applying to skin in need thereof a composition comprising at least one oxidation-sensitive hydrophilic active principle selected from the group consisting of ascorbic acid and its compounds and at least one maleic anhydride copolymer, said copolymer comprising one or more maleic anhydride comonomer units and one or more comonomer units selected from the group consisting of vinyl acetate, vinyl alcohol, vinylpyrrolidone, olefins comprising from 2 to 20 carbon atoms, and styrene, in a physiologically acceptable medium comprising an aqueous phase.  
     
     
         2 . A method according to  claim 1 , wherein said method is a method for promoting the synthesis of the epidermal ceramides and/or for improving the barrier function of the skin.  
     
     
         3 . A method according to  claim 1 , wherein said method is a method for maintaining and/or improving the radiance of the complexion.  
     
     
         4 . A method according to  claim 1 , wherein said method is a method for preventing and/or combating roughness of the skin.  
     
     
         5 . The method according to  claim 1 , wherein the hydrophilic active principle is selected from the group consisting of 5,6-di-O-dimethylsilylascorbate, the dl-α-tocopheryl 2I-ascorbyl phosphate potassium salt of ascorbic acid, magnesium ascorbyl phosphate, sodium ascorbyl phosphate and ascorbyl glucoside.  
     
     
         6 . The method according to  claim 1 , wherein the oxidation-sensitive hydrophilic active principle is ascorbic acid.  
     
     
         7 . The method according to  claim 1 , wherein the maleic anhydride units of the copolymer are in the hydrolysed form and in the form of alkaline salts.  
     
     
         8 . The method according to  claim 1 , wherein the oxidation-sensitive active principle and the copolymer are both in the aqueous phase.  
     
     
         9 . The method according to  claim 1 , wherein the copolymer has a molar fraction of maleic anhydride units of between 0.1 and 1.  
     
     
         10 . The method according to  claim 9 , wherein the copolymer has a molar fraction of maleic anhydride units of between 0.4 and 0.9.  
     
     
         11 . The method according to  claim 1 , wherein the copolymer is a copolymer of styrene and of maleic anhydride in a 50/50 ratio.  
     
     
         12 . The method according to  claim 1 , wherein the copolymer is a copolymer of styrene and of maleic anhydride in a 50/50 ratio in the form of an ammonium or sodium salt.  
     
     
         13 . The method according to  claim 1 , wherein the molar ratio of the maleic anhydride unit equivalent to the oxidation-sensitive hydrophilic active principle is from 0.005 to 10.  
     
     
         14 . The method according to  claim 13 , wherein the molar ratio of the maleic anhydride unit equivalent to the oxidation-sensitive hydrophilic active principle is from 0.01 to 1.  
     
     
         15 . The method according to  claim 1 , wherein the copolymer is present at a concentration of between 0.1 and 40% by weight of the aqueous phase.  
     
     
         16 . The method according to  claim 15 , wherein the copolymer is present at a concentration of between 0.1 and 10% by weight of the aqueous phase.  
     
     
         17 . The method according to  claim 1 , wherein the composition further comprises at least one non-ascorbic acid active principle which has an effect on the barrier function of the skin or which promotes moisturizing of the skin and/or one desquamating agent.  
     
     
         18 . The method according to  claim 17 , wherein the composition further comprises an agent selected from the group consisting of ceramides, sphingoid-based compounds, lecithins, glycosphingolipids, phospholipids, cholesterol and its compounds, phytosterols (stigmasterol, β-sitosterol or campesterol), essential fatty acids, 1,2-diacylglycerol, 4-chromanone, pentacyclic triterpenes, liquid petrolatum, lanolin, threalose and its compounds, hyaluronic acid and its compounds, glycerol, pentanediol, sodium pidolate, serine, xylitol, sodium lactate, glyceryl polyacrylate, ectoin and its compounds, chitosan, oligo- and polysaccharides, cyclic carbonates, N-lauroylpyrrolidonecarboxylic acid, N-α-benzoyl-L-arginine, DHEA and steroidal compounds, and Vitamin D and its compounds.  
     
     
         19 . The method according to  claim 17 , wherein the composition comprises an agent selected from the group consisting of β-hydroxy acids; α-hydroxy acids; urea; gentisic acid; oligofucoses; cinnamic acid; Saphora japonica extract; resveratrol; EDTA; N-acyl-N,N′,N′-ethylenediaminetriacetic acid; aminosulphonic compounds; 2-oxothiazolidine-4-carboxylic acid (procysteine) compounds; compounds of α-amino acids of glycine type; honey; or sugar compounds.  
     
     
         20 . The method of  claim 1 , wherein said method is a method for moisturizing the skin.  
     
     
         21 . The method of  claim 1 , wherein said method is a method for treating dry skin.  
     
     
         22 . A method for preparing a composition, comprising combining at least one oxidation-sensitive hydrophilic active principle selected from the group consisting of ascorbic acid and its compounds with at least one maleic anhydride copolymer comprising one or more maleic anhydride comonomer units and one or more comonomer units selected from the group consisting of vinyl acetate, vinyl alcohol, vinylpyrrolidone, olefins comprising from 2 to 20 carbon atoms, and styrene, the composition comprising an aqueous phase.