Stabilized ascorbic acid solutions; method of use thereof; process for their obtention; and compositions comprising the same

Abstract

This invention relates to improved solutions comprising ascorbic acid (vitamin C). These solutions may comprise as much as 15% ascorbic acid; they are stable for at least two years, without no significant development of yellowish coloration and no substantial (not more than 10%) degradation of the vitamin. The process involves sequential additions of ascorbic acid and ethoxydiglycol to a first solution of vitamin in water, which are followed by addition of propylene glycol. The stirring speed that occurs during the additions favors a process of micronization. Mild heating is used to achieve ascorbic acid concentrations equivalent to about 6% in 10% water or higher.

1 . A process for obtaining a stabilized ascorbic acid of a desired concentration of 15% (w/w) or less in solution, which comprises
 a) dissolving a first amount of ascorbic acid in water, thereby obtaining a first solution;   b) adding a first amount of glycol to said first solution, under a stirring speed sufficient to micronize same, ascorbic acid and water, thereby obtaining a second solution;   c) adding a second amount of ascorbic acid to said second solution under a stirring speed sufficient to micronize same, thereby obtaining a third solution;   d) adding a second amount of glycol to said third solution under high stirring speed sufficient to micronize same, thereby obtaining a fourth solution; and   e) adding another glycol, which results into the obtention of a solution of ascorbic acid having the desired concentration.   
     
     
         2 . The process of  claim 1 , which further comprises a step f) of adding an anti-oxidant to the solution of step e). 
     
     
         3 . The process of  claim 2 , which further comprises after step f), adding a fragrance material to the solution. 
     
     
         4 . The process of  claim 1 , which further comprises the step of adding a third amount of ascorbic acid between steps d) and e). 
     
     
         5 . The process of  claim 2 , which further comprises the step of adding a third amount of ascorbic acid between steps d) and e) and, when the desired concentration of ascorbic acid is more than 6% (w/w), further comprises a step of adding a fourth amount of ascorbic acid after step f), followed by a step of heating at a temperature of about 37 to 42° C. until a clear solution is obtained, followed by a step of cooling down. 
     
     
         6 . The process of  claim 5 , wherein said temperature is about 40° C. 
     
     
         7 . The process of  claim 6 , which comprises adding a fragrance material after the cooling down. 
     
     
         8 . The process of  claim 5 , which further comprises after step f) adding a fragrance material to the solution. 
     
     
         9 . The process of  claim 8 , which further comprises adding at least one topically suitable carrier or compound after the cooling step. 
     
     
         10 . The process of  claim 9 , wherein the at least one topically suitable carrier or compound comprises a topically suitable carrier or compound selected from the group consisting of tocopherol, tocopheryl acetate, retinol, retinyl palmitate, hydroquinone, proanthocyanidins, butylated hydroxytoluene, butylated hydroxyanisole, astaxanthin, alpha lipoic acid, tocotrienols, coenzyme Q10, α-hydroxy acid, kojic acid, kinetin, wine extract, vitamin K, ascorbyl palmitate, magnesium ascorbyl phosphate, sodium ascorbyl phosphate, a sun blocking agent and any combination thereof. 
     
     
         11 . The process of  claim 9 , wherein the at least one topically suitable carrier or compound comprises tocopherol. 
     
     
         12 . The process of  claim 9 , wherein the at least one topically suitable carrier or compound comprises hydroquinone. 
     
     
         13 . A solution comprising a stabilized ascorbic acid of a concentration of 15% (w/w) or less prepared by a process which comprises:
 a) dissolving a first amount of ascorbic acid in water, thereby obtaining a first solution;   b) adding a first amount of glycol to said first solution under a stirring speed sufficient to micronize the glycol, ascorbic acid and water, thereby obtaining a second solution;   c) adding a second amount of ascorbic acid to said second solution under a stirring speed sufficient to micronize same, thereby obtaining a third solution;   d) adding a second amount of glycol to said third solution under a stirring speed sufficient to micronize same, thereby obtaining a fourth solution; and   e) adding another glycol, which results into the obtention of a solution of ascorbic acid having the desired concentration.   
     
     
         14 . The solution of  claim 13 , the process further comprising a step f) of adding an anti-oxidant to the solution of step e). 
     
     
         15 . The solution of  claim 13 , the process further comprising the step of adding a third amount of ascorbic acid between steps d) and e). 
     
     
         16 . The solution of  claim 14 , which further comprises adding a fragrance material to the solution obtained after step f). 
     
     
         17 . The solution of  claim 14 , the process further comprising the step of adding a third amount of ascorbic acid between steps d) and e) and which, when the desired concentration of ascorbic acid is more than 6% (w/w), further comprises a step of adding a fourth amount of ascorbic acid after step f), followed by a step of heating at a temperature of about 37 to 42° C. until a clear solution is obtained, followed by a step of cooling down. 
     
     
         18 . The solution of  claim 17 , wherein said temperature is about 40° C. 
     
     
         19 . The solution of  claim 18 , which comprises adding a fragrance material after the cooling down. 
     
     
         20 . The solution of  claim 18 , which further comprises adding a fragrance material to the solution. 
     
     
         21 . The solution of  claim 20 , which further comprises adding at least one topically suitable carrier or compound after the cooling step. 
     
     
         22 . The solution of  claim 21 , wherein the at least one topically suitable carrier or compound comprises a topically suitable carrier or compound selected from the group consisting of tocopherol, tocopheryl acetate, retinol, retinyl palmitate, hydroquinone, proanthocyanidins, butylated hydroxytoluene, butylated hydroxyanisole, astaxanthin, alpha lipoic acid, tocotrienols, coenzyme Q10, α-hydroxy acid, kojic acid, kinetin, wine extract, vitamin K, ascorbyl palmitate, magnesium ascorbyl phosphate, sodium ascorbyl phosphate, a sun blocking agent and any combination thereof. 
     
     
         23 . The solution of  claim 21 , wherein the at least one topically suitable carrier or compound comprises tocopherol. 
     
     
         24 . The solution of  claim 21 , wherein the at least one topically suitable carrier or compound comprises hydroquinone. 
     
     
         25 . A topical composition comprising the solution of  claim 13 , and further comprising at least one topically suitable carrier or compound. 
     
     
         26 . The topical composition of  claim 25 , wherein the at least one topically suitable carrier or compound comprises a topically suitable carrier or compound selected from the group consisting of tocopherol, tocopheryl acetate, retinol, retinyl palmitate, hydroquinone, proanthocyanidins, butylated hydroxytoluene, butylated hydroxyanisole, astaxanthin, alpha lipoic acid, tocotrienols, coenzyme Q10, α-hydroxy acid, kojic acid, kinetin, wine extract, vitamin K, ascorbyl palmitate, magnesium ascorbyl phosphate, sodium ascorbyl phosphate, a sun blocking agent and any combination thereof. 
     
     
         27 . The topical composition of  claim 26 , wherein the at least one topically suitable carrier or compound comprises tocopherol. 
     
     
         28 . The topical composition of  claim 26 , wherein the at least one topically suitable carrier or compound comprises hydroquinone. 
     
     
         29 . A method for preventing or treating a disease or disorder involving or caused by reactive oxygen species, which comprises the step of topically administering a suitable amount of the solution of  claim 13 .