Eudragit-coated aceclofenac-loaded pectin microspheres in chronopharmacological treatment of rheumatoid arthritis.

The aim of this study was to develop a pectin-based colon-specific multiparticulate delivery system. Aceclofenac was used as a model drug owing to its potential therapeutic efficacy in rheumatoid arthritis. Pectin microspheres were prepared using emulsion dehydration technique. These microspheres were coated with Eudragit S-100 using solvent evaporation method. The effect of different variables (polymer, emulsifier, stirring speed and stirring time) was investigated in terms of size, surface morphology, entrapment efficiency, in vitro release and in vivo studies. The size of uncoated microspheres ranged from 30 to 55 µm and exhibited 5-40% of drug release in the upper gastrointestinal tract; however, continuous high release of drug was observed at colonic pH. In addition, the release of drug from the microspheres was found to be higher in the presence of rat cecal contents with maximum release at the 8th hour. This is one of the prerequisites for the effective treatment of rheumatoid arthritis, indicating the effect of colonic enzymes on the pectin microspheres. In vivo studies suggest the maintenance of therapeutic concentration of drug for 24 h with significant anti-inflammatory effect. Therefore, these findings clearly suggest that the Eudragit-coated pectin microspheres offer an exciting mode of aceclofenac delivery to colon in the chronopharmacological treatment of rheumatoid arthritis.