Hydrogels containing 5-fluorouracil obtained by gamma-irradiation. Synthesis, characterization and in vitro release studies

The functionalization of alpha,beta -poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA) with glycidyl methacrylate (GMA) gives rise to a water-soluble copol ymer PHEA-GMA (PHG) containing double bonds and eater groups in the side ch ain. Aqueous solutions of PHG alone or in combination with N,N ' methylenbi sacrylamide (BIS) have been exposed to a gamma -ray source at different irr adiation doses in order to obtain polymeric networks. All samples have been prepared both as water-swellable microparticles and as gel systems. Microp articles have been characterized by FT-IR spectrophotometry and swelling me asurements in aqueous media mimicking biological fluids. The effect of irra diation dose and BIS presence on theological behavior of the gel systems ha d also been investigated. All prepared hydrogels are able to incorporate, d uring gamma -irradiation, 5-Fluorouracil, (5-FU) chosen as a model drug and to release it in simulated biological fluids, as confirmed by the in vitro drug release studies at pH 1 and pH 7.4. Gels of PHG containing 5-FU, obta ined in the presence or in the absence of BIS, are able to release this dru g in a prolonged way, more slowly than a commercial ointment, as confirmed by in vitro studies at pH 5.5 and pH 7.4 using a Franz diffusion cell syste m and a synthetic membrane.