Introduction: Bioavailability issues have been an increasing concern to drug regulatory authorities once assessing the safety and efficacy of synonym drug products. Local drug regulatory authorities have, therefore, issued guidelines to ensure adequate bioavailability studies in new drug applications for synonym drugs. In the light of these considerations, the purpose of the present study was to compare the relative bioavailability of a domestic generic celecoxib capsule preparation, with that of the innovator celebrex®.
Methods: A sensitive, accurate and rapid reverse phase HPLC method was initially established to quantitate plasma levels of celecoxib in human volunteers. The drug and internal standard were extracted using n-hexane/isoamyl alcohol (97:3) and analyzed on a C18 Hichrom HPLC column, with 40% KH2PO4 (0.01M) in de-ionized water and 60% acetonitrile (PH = 3.9 - 4.1), at 255 nm. The in-vivo study was carried out in 12 healthy volunteers according to a single dose, two-sequence, cross over randomized design. The bioavailability was compared using AUC0-48, AUC0-, Cmax and Tmax. The 90% confidence intervals of the logarithmically transformed ratios of pharmacokinetic parameters of test to reference products were estimated.
Results: The standard curve covering 0.01-2.0 μg/ml concentration range was linear, relative errors were within 0.6 to 18.4 % and the CV % ranged from 7.68 to 19.04. The limits of quantitation and detection of the method were 0.01μg/mL and 0.002μg/mL, respectively. No statistically significant differences were found between the AUC0- or Cmax values of the test (Celecoxib) and reference (Celebrex®).
Conclusion: It was concluded that the generic celecoxib was bioequivalent with the innovator formulation.