Multiple emulsions contain at least three phases. The material entrapped in internal phase is released slowly and thus its effects can be prolonged. The other benefit of multiple emulsions is protection of material entrapped in internal phase. The purpose of the study was to prepare a stable multiple emulsion containing a skin antiaging agent L-Ascorbic acid (vitamin C) using paraffin oil. L-Ascorbic acid, which is a very unstable ingredient and is decomposed in the presence of oxygen, in a concentration of 2% was entrapped in the inner most aqueous phase of w/o/w multiple emulsion. Formulation of multiple emulsion was stored at different accelrated conditions i.e. 8 ºC, 25 ºC, 40 ºC and 40 ºC+75% RH (Relativ Humidity) for 28 days to predict the stability of formulation. Formulation was found to be stable at lower temperatures for a given period of time and no phase sepration was observed in any sample. Different parameters like pH, globule size, electrical conductivity and effects of centrifugation were studied for a period of 28 days to confirm the stability of multiple emulsion. It was found that there was no significant change in globule sizes in any sample kept at most of the conditions. Significant changes in both pH and conductivity were observed in the samples of formulation kept at 8 ºC. Insignificant changes both in pH and electrical conductivity were observed in samples of formulation kept at 40 ºC and 40 ºC + 75%RH conditions throughout study period. The data obtained was evaluated statistically using two way ANOVA (Analysis of Variance) and LSD (Least Significant Difference) tests.
NAVEED AKHTER ,HAJI M. SHOAIB KHAN ,NOSHEEN ZULFIQAR ,GUL FISHAN ,MAHMOOD AHMED ,TARIQ SAEED ,
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