Biodegradable microspheres of poly(DL-lactic acid) containing piroxicam as a model drug for controlled release via the parenteral route.

Poly(DL-lactic acid), synthesized in this laboratory from DL-lactic acid, was used to prepare microspheres containing piroxicam, using a solvent evaporation technique. The microspheres obtained were characterized for their surface characteristics (by SEM), surface charge, density, particle size distribution, glass transition temperature, drug incorporation and encapsulation efficiency, IR spectroscopy and in vitro drug release. The suspension of microspheres was evaluated for its syringeability. The effect of channelling agents such as PVP and PEG 6000 on in vitro drug release was studied. The effect of gamma-radiation on poly(DL-lactic acid) and on the in vitro release of piroxicam from the microspheres was also studied.