Drug Release Behaviors of a pH/Temperature Sensitive Hydrogel Bead with Core-Shelled Structure

Abstract

As a drug delivery carrier, a novel pH/temperature sensitive bead (pTSB) with core-shelled structure from poly(N-acryloylglycine) (PAG), copoly(N-acryloylglycine methyl este and N-acryloylglycine ethyl ester) was prepared by two steps. In pH=7.4 phosphate buffer solution (PBS), the cumulative release amount of indomethacin loaded in the pTSB was about 60.1 % within 500 mins, but this value only reached to 22.3 % in pH=2.1 PBS. The release behaviors of indomethacin from pTSB also exhibited a remarkable dependence on PAG content in the core. Additionally, the release rate of indomethacin was much faster at 18 oC than that at 37 oC due to the temperature sensitivity of poly(N-acryloylglycinates). The experimental results indicate that pTSB seems to have a potential application in the drug release system controlled via pH or temperature in the biomedical fields.