The study's objectives were to formulate a sustained release microsphere formulation for a poor water-soluble drug and determine the influence of processing parameters in the preparation of etodolac-loaded gum katira microspheres (ELGKM) following Wp/O/Wm emulsion solvent evaporation technique. The amount of gum katira, mechanical stirrer's stirring speed, the ratio of coating material, volume, and pH variation of the inner phase of the Wp/O/Wm emulsion system was varied to examine their effect on drug entrapment efficiency (DEE), particle size, surface morphology and in vitro drug release characteristics in dissolution media (pH-1.2 & pH-6.8). Scanning Electron Microscopic (SEM), Differential Scanning Calorimetric (DSC), and Fourier Transform Infrared (FTIR) studies were performed to find out the physicochemical as well as biopharmaceutical characterization of drug-loaded microsphere formulations. Based on experimental results, it was found that some processing variables significantly affect drug entrapment efficiency, particle size, and drug release kinetic in dissolution media. ELGKMs prepared with 50 mg Gum Katira, the ratio of Eudragit®RS100: Eudragit®RL100 at 7:1, at a stirring speed of 900 rpm showed the best formulation subjected to DEE, average particle size, and drug release profile. So, the study suggested that under the proper control of processing parameters, the Wp/O/Wm emulsion solvent evaporation technique would be a suitable method for preparing ELGKM.

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