Formulation and characterization of a multiple emulsion containing 1% L-ascorbic acid

Abstract

The purpose of the study was to prepare a stable multiple emulsion containing a skin anti-aging agent and using paraffin oil. Vitamin C, was incorporated into the inner aqueous phase of water-in.oil-in water (w/o/w) multjple emulsion at a concentration of 1%. Multiple emulsion was prepared by two step method. Stability studies ware performed at different accelerated conditions, i.e. 8°C (in refrigerator), 25°C (in oven), 40 °C (in oven), and 40 °C at 75% RH (in stability cabin) for 28 days to predict the stability of fomuilations. Different parameters, namely pH, globule size, electrical conductivity and effect of centrifugation (simulating gravity) ware determined during stability studies. Data obtained was evaluated statistically using ANOVA two way analyses and LSD tests. Multiple emulsion formulated was found to be stable at lowar temperatures (i.e. 8 and 25 °C) for 28 days. No phase separation was observed in the samples during stability testing. It was found that there was no significant change (p >0.05) in globule sizes in most of the samples kept at various conditions. Insignificant changes (p> 0.05) in both pH and conductivity values ware determined for the samples kept at 8, 40, and 40 °C at 75% RH, throughout the study period. Further studies are needed to formulate more stable emulsions with other emulsifying agents. © 2010 Chemical Society of Ethiopia.