Abstract

This study aimed to develop diclofenac sodium sustained-release tablets using different matrix systems and to evaluate their physicochemical properties. Diclofenac sodium was characterized for solubility, flowability, and particle size. Solubility in water and phosphate buffer (pH 7.5) was determined by UV-Vis spectrophotometry, while flowability was assessed via angle of repose, Hausner ratio, and Carr’s index. Product X SR 75 mg tablets were analyzed as a reference for uniformity, hardness, and dissolution. Two matrix approaches were explored: a hydrophobic system (carnauba wax and cetyl alcohol) via melt granulation and a hydrophilic system (Arabic gum) via direct compression. The research results indicate that diclofenac sodium exhibited slight solubility and poor flowability. Formulations based on both hydrophobic and hydrophilic systems were developed, meeting the physical, quantitative, and dissolution criteria of the United States Pharmacopeia (USP). The formulation exhibited a drug release profile in USP pH 7.5 medium equivalent to that of the reference product, Product X SR 75. The hydrophobic matrix formulations followed zero-order release kinetics, whereas the hydrophilic matrix formulations followed the Higuchi release model and showed stability over 3 months under accelerated and long-term aging conditions. Hydrophobic matrices provided a more sustained drug release compared to hydrophilic matrices. Both systems effectively modulated drug release, indicating their potential for once-daily extended-release diclofenac formulations.

Key words: controlled release, dissolution, diclofenac sodium, solubility, flowability, matrix system