Release of drugs from polymeric hydrogels.

Hydrogels were prepared from 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate as cross-linking agent. Two different polymerization techniques were followed, namely bulk polymerization initiated by dibenzoyl peroxide and solution polymerization, in water, using a redox initiator system. Differences in the water desorption from swollen samples between the two types of the above products were recorded and attributed to the fact that those hydrogels were obtained in glassy or rubbery state, according to the polymerization technique. Also, the delivery of salicylic acid from samples of the above types was studied, and a faster release with higher ultimate delivery was displayed by the solution polymerization hydrogels.