Formulation and in vitro evaluation of a cosmetic emulsion from almond oil

Several processes are used for the manufacture of multiple emulsions. The most widely used procedure is two step method. 1st step consists of preparing a primary emulsion. In the 2nd step, a definite amount of this primary emulsion is dispersed in an external phase containing the secondary emulsifier. Although it is a simple method, the 2nd step of the procedure includes many critical factors. In this work water-in-oil-in-water w/o/w multiple emulsion was prepared by using almond oil, Abil-EM 90, magnesium sulfate, Tween 80. The multiple emulsion was prepared by using two-step process. Stability studies of this multiple emulsion were carried out at different storage conditions i.e. 8 degrees C, 25 degrees C, 40 degrees C and 40 degrees C+ 75% relative humidity (RH) for 28 days. It was found that samples of multiple emulsion stored at 8 degrees C, 25 degrees C were stable through out the study period but samples stored at 40 degrees C and 40 degrees C+ 75% RH were found to show some changes in color, liquefaction and phase separation from third week. The changes in pH values and electrical conductivity of multiple emulsions stored at these storage conditions were also measured. Globules sizes of multiple emulsion were also measured at these storage conditions. Results indicate that there were significant changes in pH values and electrical conductivity of multiple emulsion stored at different conditions and non significant changes in globule sizes of multiple emulsion stored at these conditions were observed.