Development and Evaluation of Extended Release Ethylcellulose Based Matrix Tablet of Diclofenac Sodium

Objective: The present study involved the preparation of Diclofenac sodium extended release hydrophobic matrix tablets formulated from Ethylcellulose polymer following its different grades, Ethocel Standard Premium and Ethocel Standard FP Premium. Methods: The matrix tablets were prepared with wet granulation method. Lubricated blends were characterized for physical properties like loose bulk density, tapped density, angle of repose, Carr’s index, Hausner ́s ratio; all blends showed satisfactory properties. Tablets were evaluated for uniformity of weight, thickness, hardness, percentage (%) friability and in vitro release studies. Effect of viscosity and particle size of ethylcellulose on drug release was determined. Results: Lower viscosity grades of ethylcellulose were more compressible than higher viscosity grades, allowing production of harder tablets. Ethylcellulose grades with fine particle size showed better control on drug release rate. The release of diclofenac sodium was prolonged with increase in the concentration of ethylcellulose. Effect of diluent on drug release was also studied by comparing microcrystalline cellulose, dicalcium phosphate and lactose. Dicalcium phosphate had maximum retarding capacity followed by microcrystalline cellulose then lactose. The release kinetics of the final batch (K017) prepared using ethylcellulose followed Korsmeyer-Peppas kinetic model. Conclusion: This study reveals that a combination of low viscosity and fine particle grade (Ethocel 7cps FP Premium) was the best grade for controlling the release rate. The optimized formulation has drug release profile up to 24hours.