Hydrogels obtained by radiation-induced polymerization as delivery systems for peptide and protein drugs

The controlled release of peptides and proteins from hydrogels obtained by radiation-induced polymerization of 2-hydroxyethyl methacrylate at a low temperature was studied. It was found that the extent of release progressively decreased as protein molecular weight increased until no further release occurred above a critical value of the latter. However, an increasing rate of protein release was found if the polymerization was carried out in the presence of poly(ethylene glycol), PEG. Moreover, only with high molecular weight PEGs were large proteins released. The release data as a function of swellability and porosity of polymer matrices were discussed. (Author)