Stabilization of l -ascorbic acid in cosmetic emulsions

The prevention of the oxidation of l-ascorbic acid in cosmetic emulsions was investigated. First, its stability was tested to determine the optimum ratio, and the effects of changes in the pH, color, and concentration of l-ascorbic acid in the emulsions were investigated. The kinetics of l-ascorbic acid in emulsions were studied through HPLC. The inclusion of glycerine in the dispersion was more effective in maintaining the initial l-ascorbic acid content than the inclusion of propylene glycol, butylene glycol or DI water. A zero-order reaction model best fitted the butylene glycol-in-oil emulsion, whereas a first-order model best fitted the water-in-oil emulsion.