Radioprotective Efficacy of Phosphorus-Containing Polymer Complexes of Amifostine WR-2721

Background: The aim of this study was to investigate the radioprotective efficacy of polymer complexes constructed from amifostine (WR-2721) and poly(hydroxyoxyethylene phosphate)s with different molecular weights. The use of suitable polymers for the immobilization of radioprotective drugs is aimed at improving or obtaining important new properties. Methods: The radioprotective efficacy of the compounds was investigated by cytotoxicity and the survival of mouse embryonic fibroblasts MEF LIG4+/+ and MEF LIG4−/− cells irradiated with 2, 6 and 12 Gy in the presence of amifostine (WR-2721) and its polymer complexes. Results: The radioprotective efficacy of the polymer complexes constructed of amifostine (WR-2721) and poly(hydroxyoxyethylene phosphate)s with different molecular weights showed promising activity and dose regimens. Conclusions: Cytotoxicity studies for tested cell lines MEF LIG4+/+ and MEF LIG4−/− cells showed that the polymer complexes were not toxic when equivalent doses of the drug amifostine (WR-2721) were applied to the cells. Irradiated MEF LIG4+/+ cells demonstrated an increase in the surviving fraction when pre-treated with 0.5–5 mM polymer complexes when equivalent doses of amifostine (WR-2721) were applied to the cells and irradiated. The radioprotective efficacy had increased when the cells MEF LIG4+/+ were irradiated with 12 Gy. These findings demonstrate that poly(hydroxyoxyethylene phosphate)s are suitable carriers of the radioprotective drug amifostine (WR-2721). They further suggest that they may be interesting for researchers seeking new challenges in discovering advanced radioprotective active substances.