抄録
Interpenetrating polymer network (IPN)s composed of poly(acrylamide(AAm)-co-butyl methacrylate(BMA)) and poly (acrylic acid) (PAAc) were investigated in terms of temperature dependence of swelling and drug release behavior to achieve effective thermo-responsive drug delivery system. The two polymers used as ingredients for the IPNs form interpolymer complex by hydrogen bonding and precipitate at lower temperatures in water, and at higher temperatures the complex dissociates and the polymers are solubilized. The IPNs constructed from the polymers showed low swelling ratio in a lower temperature range and high swelling in a higher temperature range, exhibiting drastic swelling change at around 25°C. It is explained that such temperature-dependent swelling behavior with transition of the IPNs was attributed to drastic formation/dissociation alteration of polymer complex induced by a zipper effect with temperature. The IPNs also demonstrated reversible swelling/shrinking changes with temperature fluctuations. Further, drug release from the IPNs was conducted using ketoprofen as a model drug. On-off releases responding temperature change, i. e “on” release at high temperature and “off” release at low temperature, were observed for IPNs containing proper amounts of BMA. Release rate in “on” state could be regulated by changing BMA content.
