Diclofenac sodium incorporated PLGA (50 : 50) microspheres: formulation considerations and in vitro/in vivo evaluation

Recently, considerable interest has been focused on the use of biodegradabl e polymers for specialized applications such as controlled release of drug formulations; meanwhile, microsphere drug-delivery systems using various ki nds of biodegradable polymers have been studied extensively during the past two decades. Poly (lactide-co-glycolide) (PLGA) polymers have been proven to be excellent drug carriers for microparticulate systems due to their adv antages, e.g. biocompatibility and regulatory approval. The administration of nonsteroidal anti-inflammatory drugs (NSAIDs) into the intra-articular c avity in patients with chronic inflammatory disease is complicated due to t he short duration of effect. In the present study, controlled-release paren teral formulations of diclofenac sodium (DS), a commonly used NSAID, were p repared for intra-articular administration, and evaluated in vitro for part icle size, yield, drug loading, surface morphology and release characterist ics. For in vivo studies, Technetium-99m labelled polyclonal human immunoga mmaglobulin ((99m) Tc-HIG) was used as the radiopharmaceutical to demonstra te arthritic lesions by gamma scintigraphy. Evaluation of arthritic lesions post-therapy in rabbits showed no significant difference in the group trea ted with PLGA (50:50) (mw 34 000) DS microspheres compared to control group s. (C) 2000 Elsevier Science B.V. All rights reserved.