Preparation and application in drug controlled delivery of pH-sensitive P(CE-co-DMAEMA-co-MEG) hydrogel

A pH-sensitive hydrogel [P(CE- co -DMAEMA- co -MEG)] was synthesized by the free-radical crosslinking polymerization of N,N -dimethylaminoethyl methacrylate (DMAEMA), poly(ethylene glycol) methyl ether methacrylate(MPEG-Mac) and methoxyl poly(ethylene glycol)-poly(caprolactone)-methacryloyl methchloride (PCE-Mac). The effects of pH and monomer content on swelling property, swelling and deswelling kinetics of the hydrogels were examined and hydrogel microstructures were investigated by SEM. Sodium salicylate was chosen as a model drug and the controlled-release properties of hydrogels were pilot studied. The results indicated that the swelling ratios of the gels in stimulated gastric fluids (SGF, pH = 1.4) were higher than those in stimulated intestinal fluids (SIF, pH = 7.4), and followed a non-Fickian and a Fickian diffusion mechanism, respectively. In vitro release studies showed that its release rate depends on different swelling of the network as a function of the environmental pH and DMAEMA content. SEM micrographs showed homogenous pore structure of the hydrogel with open pores at pH 1.4. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 40737.