Comparative bioavailability of two cetirizine tablet formulations in Indonesian healthy volunteers

Aim: To compare the bioavailability of two cetirizine tablet (10 mg) formulations (Zyrtec® from UCB Pharma, Spain as a reference formulation and Ryvel® from Novell Pharmaceutical Laboratories, Indonesia as a test formulation). Material and methods: The study was conducted according to an open, randomized, two-period crossover design with a 1-week washout period. Eighteen volunteers participated and all completed the study successfully. Blood samples were obtained prior to dosing and at 0.25, 0.5, 1, 2, 3, 5, 8, 12, 24 and 30 hours after drug administration. Plasma concentrations of cetirizine were monitored using high-performance liquid chromatography over a period of 30 hours after administration. The pharmacokinetics parameter AUC_0-30h, AUC_0-∞ and C_max were tested for bioequivalence after log-transformation of data and ratios of t_max were evaluated non-parametrically. Result: The point estimates and 90% confidence intervals for AUC_0-30h, AUC_0-∞ and C_max were 108.23% (101.90 - 114.95%), 108.11% (101.91 - 114.68%) and 99.71% (90.18 - 110.25%), respectively, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products an the US Food and Drug Administration guidelines. Conclusion: These results indicate that two medications of cetirizine are bioequivalent and, thus, may be prescribed interchangeably.