Research progress of pickering emulsion drug delivery systems

Pickering emulsion is a new type of emulsion which is stabilized by the adsorption of solid particles on the interface of emulsion droplets. In recent years, its applications in pharmacy have attracted more and more attention because of its higher resistance to coalescence and better safety than traditional surfactant emulsions. The Pickering emulsion was first used for topical administration to reduce skin irritation of surfactants and promote transdermal absorption of drugs. Recently, new oral and injectable Pickering emulsions have also been reported, which can promote oral absorption of insoluble drugs, improve stability of drugs, control drug release, targeted-delivery drugs, and serve as the carrier for novel immunological adjuvants. All these studies show Pickering emulsion a promising drug delivery system. However, its development in pharmacy is still in its infancy. There are many factors influencing the preparation of Pickering emulsions. But there is no systematic analysis of these factors up to now. In this review, we gave an overview of Pickering emulsions from their application in pharmaceutical field, preparation and evaluation, focusing on the effects of solid particles, oil phase, preparation technology and interaction of various factors on the fabrication of Pickering emulsions. The challenges and future directions of this exciting and rapidly expanding research area were further commented on, in order to provide reference for the in-depth study of Pickering emulsion drug delivery systems.