Three-ply walled w/o/w microcapsules formed by a multiple emulsion technique.

A new method of microencapsulation is described. Interfacial rheological studies had shown the formation of a rigid bipolymer film at the interface between an aqueous solution of a water-soluble polymer and a non-aqueous solution of an oil-soluble polymer. This led to the idea that small spherical bodies might be formed on making a w/o/w emulsion from these solutions. The present work has shown that ethyl cellulose/acacia microcapsules are formed when the organic solvent ethyl acetate is removed from the multiple emulsion drops. These microcapsules may be obtained as a free-flowing powder.