Protein microspheres as suitable devices for piroxicam release

Bovine serum albumin-piroxicam (BSA-piroxicam) and human serum albumin-piroxicam (HSA-piroxicam) microspheres were sonochemically prepared and characterized. The use of polyvinyl alcohol (PVA) lead to an improvement of formulation characteristics, including smaller size, lower polydispersity index (PDl), higher entrapment efficiency and higher stability. The release kinetics of these proteinaceous microspheres was determined in presence of protease, indicating an anomalous drug transport mechanism (diffusion and polymer degradation). In presence of higher protease concentration, BSA microspheres exhibit Case II transport, leading to zero order release (protein degradation). These proteinaceous devices did not show cytotoxicity against human skin fibroblasts in vitro, for range concentrations below to 300 mg L−1, greatly supporting their potential application in the treatment of inflammatory diseases.We would like to acknowledge the financial support of European project Lidwine (contract no. NMP2-CT-2006-026741), and to POPH/FSE for co-financing and FCT for fellowship SFRH/BPD/38939/2007