Synthesis and Characterization of pH-Responsive P(MAA-co-EGMA) Hydrogel Microparticles for Intelligent Drug Delivery System

Environmentally responsive materials show drastic changes in their swelling ratio in response to changes in their external pH, temperature, nature and composition of the swelling agent, and electrical or magnetic stimulus. The drastic swelling change can be used in the design of an intelligent drug delivery system. In this study, we developed the novel method to synthesize the pH-responsive P(MAA-co-EGMA) hydrogel particles with micro- or nanoscales using dispersion photopolymerization or supercritical fluid system. We also evaluated the feasibility of the P(MAA-co-EGMA) hydrogel particles as the biological on-off switch for an intelligent drug delivery triggered by an external pH change. The particles having a spherical shape were obtained with an average size in the range between 500 nm and 3 μm depending on the synthesis method. In addition, the P(MAA-co-EGMA) hydrogel particles showed a typical pH-responsive swelling and release behaviors of the anionic hydrogels.