Emulsion Stabilized by Pickering Emulsion Polymerization Technique: A State-of-the-Art Review

Pickering emulsion is an attractive approach for developing stabilized emulsions. It has proved its potential use not only in the food industry but also in the pharmaceutical industry. The use of surfactants in ocular and other parenteral drug delivery systems is limited due to their potential to cause allergic reactions, thereby limiting the application of emulsions as drug delivery routes in the pharmaceutical industry. Pickering emulsion is known for imparting better stability to emulsions with respect to Ostwald ripening and destabilization under varying environmental conditions. The technique involves surrounding the micelle with solid particles, resulting in modified physicochemical properties of the developed carrier. It also allows preventing the use of surfactants that are currently considered toxic by regulatory authorities for human use. Various organic polymers such as starch, chitosan, soy protein, ovotransferrin, and gums, among others with amphiphilic characteristics, have been investigated for the development of new drug delivery or monolithic systems using the Pickering emulsion technique. Pickering emulsion offers opportunities to develop not only O/W and W/O emulsions but also multiple emulsions and surface modifications with different active functionalities to impart stimuli-responsive drug release. Despite the broad scope of pharmaceutical applications, controlling polydispersity, maintaining particle integrity while dealing with proteins, ensuring industrial scalability, and achieving low production costs are some of the key challenges with Pickering emulsions. Future developments may include multifunctional carriers capable of simultaneous drug delivery and diagnosis, thereby enabling personalized therapeutic treatments with controlled delivery profiles. Consequently, Pickering emulsions make targeted delivery, controlled release, and enzyme immobilization possible for challenging drug molecules.