Formulation Development and Evaluation of Diclofenac Sodium Loaded Sustained Release Pellets

The objective of this study was to formulate and evaluate sustained release (SR) pellets of Diclofenac Sodium using ethyl cellulose as a release-retarding polymer. Diclofenac Sodium, a widely used NSAID, suffers from a short biological half-life and associated gastrointestinal side effects due to frequent dosing. To overcome these limitations, SR pellets were developed via a solution-layering technique using nonpareil seeds, HPMC E5 as a binder, and ethyl cellulose at varying concentrations (1%, 3%, and 5%) as a coating polymer. The formulated pellets (F1–F3) were evaluated for particle size, flow properties, friability, drug content, surface morphology, and in vitro drug release. Results indicated an increase in mean particle size with higher polymer concentration, suggesting uniform and successful coating. All formulations exhibited excellent flow properties demonstrating mechanical robustness. Drug content study indicating uniform drug distribution. SEM analysis of the optimized formulation (F3) revealed smooth, spherical pellets with a uniform coating layer. In vitro drug release studies demonstrated that higher concentrations of ethyl cellulose slowed drug release F1 released 96.64% in 8 hours, F2 in 10 hours, and F3 in 12 hours. This sustained release was attributed to the hydrophobic nature of ethyl cellulose, which formed a semi-permeable barrier controlling drug diffusion. Overall, formulation F3 exhibited the most desirable sustained release profile, making it a promising candidate for once-daily dosing of Diclofenac Sodium, thereby enhancing therapeutic efficacy and patient compliance.