Oral bioavailability and pharmacokinetic study of cetrizine HCl in Iranian healthy volunteers.

The objective of the present study was to evaluate the pharmacokinetic parameters and bioavailability of a selective histamine (H1)-receptor antagonist, cetirizine hydrochloride (CTZ), following administration of a single oral dose of the drug. The properties of a test compound were compared with those of a reference product in a randomized cross-over study in 12 volunteers. Blood samples were collected at selected time intervals up to 24 h and plasma concentrations of CTZ were determined using a validated HPLC method. Pharmacokinetic parameters including T(1/2), T(1/2)(abs), K, K(a), T(max), C(max), V(d)/F, Cl/F, AUC(0-24), AUC (0-∞) and MRT were determined from plasma concentration-time profiles for tested products and found to be in good agreement with previous reports. The analysis of variance did not show any significant differences between the test and reference products. The confidence intervals for the ratio of C(max) (95-110%), AUC(0-24) (91-112%) and AUC(0-∞) (92-109%) for the test and reference products were within the acceptable interval of 80-125%. ANOVA assessment of logarithmically transformed data did not reveal any significant subject, period or sequence effects. It was, therefore, concluded that the two products were bioequivalent and could be used interchangeably.