Polymeric microspheres composed of pH/temperature-sensitive polymer complex

A new pH/temperature-sensitive polymer system with transitions resulting bo th from polymer-water and polymer-polymer interactions has been demonstrate d 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 d rug. This gave the control of hydrocortisone release in an on-off manner wi thout considerable lag time. (C) 2001 Elsevier Science Ltd. All rights rese rved.