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 ma ny ways. They are made of small oily drops (intermediate phase) disper sed in an aqueous medium (outer phase) and in which very small aqueous droplets (inner phase) are encapsulated. These systems protect the su bstances encapsulated in the inner phase and can prolong their release to the outer phase. This work has developed a W/O/W emulsion containi ng active substances in each of the phases. The study of the release o f the substance encapsulated in the inner aqueous phase, using rheomet ry and conductimetry, has shown that two simultaneous release mechanis ms can exist: a breakdown of the oily membrane followed by the expulsi on of the encapsulated substance and a diffusion of this substance thr ough this oily membrane. These observations should allow to control th e release of the entrapped substance.