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Efficacy of chitosan microspheres for controlled intra‐articular delivery of celecoxib in inflamed joints

The use of polymeric carriers in formulations of therapeutic drug delivery systems has gained widespread application, due to their advantage of being biodegradable and biocompatible. In this study, we aimed to prepare celecoxib‐loaded chitosan microspheres for intra‐articular administration and to compare the retention of the celecoxib solution and chitosan microspheres in the joint cavity. The microspheres were characterized for entrapment efficiency, particle size and surface morphology by scanning electron microscopy. In‐vitro drug release studies of microspheres revealed that the microspheres are able to control the release of celecoxib over a period of 96 h. Biodistribution studies of celecoxib and chitosan microspheres were performed by radiolabelling with 99mTc and injecting intra‐articularly in rats. The study indicated that following intra‐articular administration the distribution of the drug to the organs, like liver and spleen, is very rapid compared with that of the microspheres. Compared with the drug solution, a 10‐fold increase in the concentration of the drug in the joint was observed 24 h post intra‐articular injection (P < 0.005) when drug was encapsulated in microspheres.