Intra-articular lornoxicam loaded PLGA microspheres: enhanced therapeutic efficiency and decreased systemic toxicity in the treatment of osteoarthritis

The aim of this study was to investigate the joint tissue distribution and pharmacodynamics of Lornoxicam (Lnxc) following intra-articular injection of either Lnxc suspensions or sustained release Lnxc-loaded PLGA microspheres (Lnxc-MS), as well as the biocompatibility of PLGA microspheres with or without drugs. In this study, Lnxc suspensions or Lnxc-loaded PLGA microspheres was injected into the knee joint cavity of rats. Blood samples were taken at predetermined times from the jugular vein and the joint tissue (cartilage and synovial membrane) were removed from the rats. Biocompatibility and pharmacodynamics were evaluated by observing the swelling of the joints of the rats and histological analysis following the injection of the microspheres. The plasma drug concentration decreased in rats and retention time increased in rats' joint with intra-articular injections of microspheres, revealing good targeting efficiency and decreased systemic toxicity. After 30 days of intra-articular injection with Lnxc-loaded or blank microspheres, the filtration liquid accumulation, blood vessels and fibrous proliferation were not detected, showing their good compatibility. Furthermore, the articular cartilage damage by papain could also be repaired by the Lnxc-loaded PLGA microspheres. In conclusion, intra-articular Lnxc-MS have considerable potential for creating a sustained release Lnxc delivery system and providing effective healing to Osteoarthritis.