Highly crosslinked, PEG-containing copolymers for sustained solute delivery.

Novel ionizable polymer networks were prepared from oligo(ethylene glycol) (OEG) multiacrylates and acrylic acid (AA) employing bulk radical photopolymerization techniques. The properties of these materials exhibited a complex dependence on the network structure and composition, and the materials were therefore used in the design of controlled release devices with precisely controlled properties. The release kinetics of model solute proxyphylline exhibited a strong compositional dependence, with measured diffusion coefficients varying over several orders of magnitude, depending on the polymer network structure and the pH of the release medium. Varying the OEG chain length provided a means of coarsely adjusting the proxyphylline release rate, while varying the AA content and the pH offered a more precise measure of control.