Novel blends of poly[bis(glycine ethyl ester) phosphazene] and polyesters or polyanhydrides: compatibility and degradation characteristics in vitro

Poly[bis(glycine ethyl ester)phosphazene] (PGP) was blended with poly(D,L-l actide) (PLA), poly(D,L-lactide-co-glycolide) (80:20 by mole) (PLGA), poly( sebacic anhydride) (PSA) and poly (sebacic anhydride-co-trimellitylimidogly cine)-block-poly(ethylene glycol) (30:50:20 by mole) (PSTP) in various rati os using a solvent-mixing technique. The compatibility of these blends has been evaluated by DSC, FTIR and phase contrast microscopy. The results indi cated that PGP is completely incompatible with PLA, but partially compatibl e with PLGA and PSTP, which may be attributed to a hydrogen bonding effect. Degradation experiments have been conducted in distilled water at 37 degre esC and show that the blend degradation rate can be regulated by adjusting the PLGA or PSTP content of the blends. PGP/PLGA (70:30 by wt) slabs took 1 20 days to disappear completely, while PGP/PSTP (70:30 by wt) slabs needed only 20 days. These findings suggest that blends of PGP and PLGA or PSTP ma y be used as matrices for drug controlled release and for other potential b iomedical applications. (C) 2000 Society of Chemical Industry.