pH-Responsive Hydrogel with Controlled Swelling and Degradation Rate

A range of hydrogels were prepared by solution polymerization of methacrylic acid, poly(ethyleneglycol) methyl ether methacrylate (M.W. 475 g/mol) and poly(ethyleneglycol) dimethacrylate (as the cross-linking, M.W. 550 or 875 g/mol) in various proportions. The effects of methacrylic acid/ poly(ethyleneglycol) methyl ether methacylate concentration ratios as well as cross-linking concentration in the degree of swelling as a function of the media pH were studied. Reversibility of the swelling process was confirmed. Degradation in the system described previously was introduced using a hydrolytically labile diacrylate cross-linker (A-PLA-PEG-PLA-A) instead of the poly(ethyleneglyco) dimethacrylates. The degrees of swelling and degradation rates at different pH were studied. Hydrolytically degradable polymers that respond to pH stimuli to activate the swelling and decomposition process were developed. Multiple interrelated control parameters dictated by the synthetic recipe were studied and are available to separately control swelling and degradation rates of these novel polymers.