Synthesis and Performance of pH-Sensitive Hydrogel Microspheres and In Vitro Evaluation as Potential Drug Carriers

To accelerate the response rate of smart hydrogels to the environmental conditions, a novel pH-sensitive hydrogel microsphere with the controlled shapes and sizes were developed. Such monodispersed microspheres were synthesized via free radical polymerization under the protection of a multilayer stability system. The pH-responsibility of hydrogel microspheres was tested with the hydrogel bulk as a control. In vitro release studies were conducted in the simulated gastric fluid and intestinal juice with bovine serum albumin (BSA) as a model drug. The large specific surface areas endowed hydrogel microspheres a faster pH-responsibility than that of bulk ones. Therefore, such microspheres showed potential applications as the oral protein drugs carrier.