Preparation of temperature-sensitive poly(N-isopropylacrylamide)/β-cyclodextrin-grafted polyethylenimine hydrogels for drug delivery

In this study, novel thermally sensitive semi-interpenetrating polymeric network hydrogels composed of poly(N-isopropylacrylamide) (PNIPAAm) and beta-cyclodextrin-grafted polyethylenimine were prepared by radical polymerization. Compared to normal PNIPAAm hydrogels, the semi-interpenetrating network hydrogels had a higher swelling ratio at room temperature and exhibited faster shrinking kinetics when the temperature was elevated to above the lower critical solution temperature. Propranolol as a model drug was loaded into the gels, and the release results show that compared to that of the normal PNIPAAm hydrogel, the release time of propranolol from the cyclodextrin-containing gel was prolonged. These improved drug-release properties may have been due to the formation of inclusion complexes between the drug molecules and cyclodextrin groups. (C) 2008 Wiley Periodicals, Inc.