- M Kurisawa: School of Materials Science, Japan Advanced Institute of Science and Technology, Ishikawa, Japan.
Interpenetrating polymer network (IPN)-structured hydrogels of gelatin (Gtn) and dextran (Dex) were prepared with lipid microspheres (LMs) as a drug microreservoir, and LM release from these hydrogels was examined in relation to their dual-stimuli-responsive degradation. A phase morphology in the IPN-structured hydrogels was varied with the preparation temperature, i.e. above or below the sol-gel transition temperature (Ttrans) of Gtn. The IPN-structured hydrogel prepared below Ttrans exhibited a specific degradation-controlled LM release behavior: LM release from the hydrogel in the presence of either alpha-chymotrypsin or dextranase alone was completely hindered, whereas LM release was observed in the presence of both enzymes. It is concluded that dual-stimuli-responsive drug release can be achieved by specific degradation of a particular IPN-structured hydrogel.