A TOPICAL W/O/W MULTIPLE EMULSION CONTAINING SEVERAL ACTIVE SUBSTANCES - FORMULATION, CHARACTERIZATION AND STUDY OF RELEASE

W/O/W multiple emulsions are vesicular systems which can be used in many ways. They are made of small oily drops (intermediate phase) dispersed in an aqueous medium (outer phase) and in which very small aqueous droplets (inner phase) are encapsulated. These systems protect the substances encapsulated in the inner phase and can prolong their release to the outer phase. This work has developed a W/O/W emulsion containing active substances in each of the phases. The study of the release of the substance encapsulated in the inner aqueous phase, using rheometry and conductimetry, has shown that two simultaneous release mechanisms can exist: a breakdown of the oily membrane followed by the expulsion of the encapsulated substance and a diffusion of this substance through this oily membrane. These observations should allow to control the release of the entrapped substance.