In vitro and in vivo degradation study on novel blends composed of polyphosphazene and polyester or polyanhydride

Poly[bis(glycine ethyl ester)phosphazene] (PGP) was blended with poly(D,L-lactide-co-glycolide) (80:20 by mole) (PLGA) and poly[sebacic anhydride-co-trimellitylimidoglycine)-block-poly(ethylene glycol)] (30:50:20 by mole) (PSTP) in various ratios using a solvent-mixing technique. The in vitro degradation of polymer blends was examined by treatment in distilled water with or without lipase at 37degreesC; the degradation rate of the blends could be regulated by adjusting the composition. PGP/PLGA (70:30 by wt) slabs took 120 days to disappear completely, while PGP/PSTP (70:30 by wt) needed only 20 days. Furthermore, Rhizopus delemer lipase showed the strongest acceleration activity on PGP/PLGA blends. The degree of enzymatic degradation was proportional to the percentage of PLGA in the blend. For comparison, the in vivo degradation of polymer blends was investigated by implanting them subcutaneously in the back of mice, some difference in degradation being observed. (C) 2002 Society of Chemical Industry.