Bioequivalence Study of Diclofenac 150 mg XR: A Single-Dose, Randomized, Open Label, 2-Period Crossover Study in Healthy Adult Volunteers

Objectives: Evaluate the bioequivalence (BE) of two oral tablets formulations of diclofenac 150 mg in healthy male subjects under fasting condition. This was a phase I, randomized, open label, balanced, two period, two sequences, single oral dose, crossover, analyst blind study. Methods: Twenty four (24) healthy subjects were randomly assigned to one of two sequences protocol: 150 mg XR of reference formulation (R), diclofenac sodium in the first period or the test formulation (T), diclofenac potassium in the second or vice versa. The plasma concentrations were determined using a validated LC-MS/MS method. Pharmacokinetic (PK) parameters included: maximum plasma concentration (Cmax), area under the plasma concentration—time curve from time 0 to the last measurable concentration (AUC0-t), and area under the plasma concentration—time from time 0 to infinity (AUC0-∞), were evaluated for BE. Results: The results showed that 90% confidence intervals for the test/reference geometric mean ratios (GMR) of Cmax (90.43 - 107.17), AUC0-t (93.08 - 116.46) and AUC0-∞ (92.52 - 117.39) were within the BE (80% - 125%) acceptance range. Conclusions: Two formulations, reference product (R) Voltaren® (diclofenac sodium) of Novartis and test product (T), Diklason Bi (diclofenac potassium) of Laboratorios Leti S.A.V., with a single dose of 150 mg XR, under fasting conditions were bioequivalent. No severe, serious or unexpected adverse events (AEs) were reported in this study.