Transparent macroemulsions for cosmetic applications

Synopsis This study proposes a method for preparation of transparent emulsions for cosmetic applications. The continuous phase in oil-in-water emulsions consisted of both water and several polyols in order to equalize the refractive indices of the two phases. Sorbitol, glycerol and mannitol were the main polyols used in the adequate concentration and isopropyl myristate was the oil phase. Stabilities of a few days in 60 degrees C incubation and a few months on the shelf were obtained. Combinations of triethanolamine oleate together with sorbitan esters and ethoxylated sorbitan esters were found to improve the emulsion stability. The optimal water concentration was checked by spectrophotometer measurements at 660 nm in order to achieve best transparency. In conclusion, it was demonstrated that relatively stable transparent macroemulsions can be prepared by equalizing the refractive indices of the two phases composing the emulsion.