A THERMOSENSITIVE HYDROGEL - POLY(ETHYLENE OXIDE-DIMETHYL SILOXANE-ETHYLENE OXIDE) POLY(N-ISOPROPYL ACRYLAMIDE) INTERPENETRATING POLYMER NETWORKS .2. ON-OFF REGULATION OF SOLUTE RELEASE FROM THERMOSENSITIVE HYDROGEL

Interpenetrating polymer networks (IPNs) of poly(ethylene oxide-dimethyl siloxane-ethylene oxide) (PEO-PDMS-PEO) ABA triblock copolymer and poly(N-isopropyl acrylamide) (PIPAAm) has been synthesized as thermosensitive gels. Indomethacin and ketoprofen were selected as model drugs and incorporated into thermosensitive gel. Pulsatile drug release produced from these thermosensitive gels was strongly influenced by the swelling-deswelling kinetic properties of thermosensitive gels solubility dependence of drug as a function of temperature, and the temperature applied. However, the release behavior of indomethacin and ketoprofen at several fixed temperatures from the thermosensitive gel showed similar patterns. The exact initiation temperatures for drug release of both drugs were similar and slightly below the swelling transition temperature of an unloaded gel. © 1990 The Society of Polymer Science, Japan.