Chiang Mai Journal of Science

 The development of amphiphilic copolymers with pH- and temperature-responsive  properties by grafting isopropyl amine and poly(ethylene glycol) monomethyl ether onto poly(styrene-alt-maleic anhydride) copolymer for drug delivery of ibuprofen as the model drug is reported. The modified hydrogel matrices were studied by FT-IR spectroscopy. The synthesized hydrogel behaves as a “smart” dual-responsive material showing transition at the temperature/pH values close to the physiological ones. Hence, swelling and release kinetic studies were performed at 37 °C in acid medium, at pH=3, for mimicking conditions of the gastric fluid in the stomach. The release of the drug was monitored by UV-Vis. spectrophotometer. In order to study the release kinetics, experimental data obtained from in vitro drug release were approximated by several mathematical models including zero-order, first-order, Hixson-Crowell and Korsmeyer-Peppas to determine the kinetics of drug release from drug delivery systems. The quantitative analysis can ultimately help to yield information on the efficacy of various release models. The results obtained showed that the Korsemeyer–Pappas model fits well to data of ibuprofen release.