Polymeric microspheres composed of pH/temperature-sensitive polymer complex

A new pH/temperature-sensitive polymer system with transitions resulting both from polymer–water and polymer–polymer interactions has been demonstrated using the mixture of poly(N,N-dimethylamino)ethyl methacrylate (DMAEMA) and polyethyl acrylamide (EAAm). Based on the pH/temperature sensitivity of polymer mixture, the microsphere for pH/temperature-sensitive drug release have been designed and characterized. Hydrocortisone was used as a model drug. This gave the control of hydrocortisone release in an on–off manner without considerable lag time.