Bioequivalence and Physiologically Based Pharmacokinetic (PBPK) Modeling of Etoricoxib Tablets in Local Population: A Comparative Pharmacokinetic Study

Systematic reviews and original research articles should have a structured abstract of around 250 words and contain the following headings: Background/Objectives, Methods, Results, and Conclusions. Background/Objectives The study involves assessment of bioequivalence of a locally manufactured etoricoxib film-coated tablet (test) relative to the reference product, followed by Physiologically based pharmacokinetic (PBPK) modeling. Methods: In-vitro dissolution testing was performed in media of pH 1.2, 4.5, and 6.8 using USP Apparatus II (paddle method). A randomized, open-label, two-treatment, two-period, single-dose crossover study was conducted in 12 healthy Pakistani male volunteers under fasting conditions. Subjects received a single 120 mg dose of either the test (Etoxib®) or reference (Arcoxia®) product, with a 14-day washout. Plasma etoricoxib concentrations were quantified over 72 hours using a validated HPLC-UV method, and pharmacokinetic parameters were determined via non-compartmental analysis. Results: The geometric mean ratios (90% confidence intervals) for Cmax, AUC₀–t, and AUC₀–∞ were 0.946 (0.8855–1.0135), 0.923 (0.8705–0.9795), and 0.960 (0.8955–1.0255), respectively, within the regulatory bioequivalence range. Both formulations were well-tolerated, with no serious adverse events reported. PBPK modeling of in vivo pharmacokinetic data demonstrated acceptable fold errors for assessed parameters, supporting the bioequivalent findings. Conclusions: The study confirms that the locally made etoricoxib tablet is bioequivalent to the reference product, with pharmacokinetic parameters that meet regulatory standards. The PBPK modeling showed acceptable results, proving the test product is a therapeutically equivalent option.