Pendent chain linked delivery systems: I facile hydrolysis through anchimeric effect

This paper describes a strategy to design catalytic hydrogels for the controlled release of pendent chain linked active ingredients under physiological conditions. It involves the organization of the polymer structure to bring the catalytic groups in proximity of the polymer-drug conjugate. Polymerization of the charge transfer complex between N-vinyl imidazole and p-nitrophenyl p-vinyl benzoate with 2-hydroxyethyl methacrylate, results in catalytic hydrogels in which the catalytic and substrate sites are on the same chain and are located next to each other. This leads to enhanced hydrolysis rates under facile conditions. Since the catalytic activity of imidazole is a function of pH, such hydrogels could be exploited as pH responsive delivery systems.