Abstract
Topical products are not stable following application to the skin due to the evaporation of volatile components. Such changes have been demonstrated in liquid emulsions, but there is almost no study available for creams in this respect. The aim of the present investigation is to evaluate the changes in cream properties following topical application and their influence on product efficiency. A method has also been designed and validated to mimic cream application to the skin. To perform this investigation, five different creams were prepared and alterations of type of creams, size of droplets of the dispersed phase, occlusivity, water content and rate of water loss were studied after application. These changes were then attributed to the type of cream, water content, presence of humectant, and time post application. The results demonstrated that creams changed intensely after application, including the phase inversion of O/W formulations, changes in the occlusivity of creams, reduction of water content, rate of water evaporation and droplet size. Such changes could be controlled partly by humectants. The present results suggest that formulators should be aware of such possible changes and required precautions should be taken in advance.