Development of a single combined microencapsulated formulation of allopurinol and nimesulide and investigation of their release behaviours

The aim of this study was to develop a single combined once-daily sustained release microencapsulated dosage form of Allopurinol and Nimesulide using Ethyl cellulose as release controlling factor and to evaluate drug release parameters as per various release kinetic models. In order to achieve required sustained release profile, microparticles were prepared using coacervation thermal change technique. The formulated microparticles were also characterized by physical and chemical parameters and results were found in acceptable limits. Different dissolution models were applied to drug release data in order to evaluate release mechanisms and kinetics. The drug release data fit well to the Higuchi expression. Drug release mechanism was found as a complex anomalous one