Recent Trends in Multiple Emulsion-A Comprehensive Review

Abstract

Multiple emulsions are complex polydispersed systems where both oil in water and water in oil emulsion exists concurrently which are stabilized by lipophillic and hydrophilic surfactants respectively. The ratio of these surfactants is important in achieving stable multiple emulsions. Among water-in-oil-in-water (w/o/w) and oil-inwater-in-oil (o/w/o) type multiple emulsions; the previous has wider areas of application. Formulation, preparation techniques and in vitro characterization methods for multiple emulsions are reviewed. It finds extensive range of applications in controlled or sustained drug delivery, targeted delivery, taste masking, bioavailability improvement, enzyme immobilization, etc. Multiple emulsions have also been employed as transitional step in the microencapsulation process and are the systems of increasing interest for the oral delivery of hydrophilic drugs, which are unbalanced in gastrointestinal tract like proteins and peptides Preparation of monodispersed multiple emulsion is important in DDS to improve their stability and to facilitate control of their properties. The study concluded that stable multiple emulsion with high entrapment efficiency can be prepared by two step emulsification method using Spans40, 60, 80 as primary emulsifier and Tween80 as secondary emulsifier.