Abstract
Fexofenadine, one of selective histamine $H_1$ receptor antagonists, has been used for the treatment of seasonal allergic rhinitis and chronic idiopathic urticaria. The bioequivalence of two fexofenadine hydrochloride preparations, containing 180 mg fexofenadine hydrochloride, was evaluated according to the guidelines of Korea Food & Drug Administration (KFDA). The test product was Hanmi Fexofenadine Hydrochloride $Tablet^{\circledR}$ made by Hanmi Pharm. Co. and the reference product was Allegra $Tablet^{\circledR}$ made by Handok Parmaceuticals Co.. Twenty healthy male subjects were randomly divided into two groups and a $2\;{\time}\;2$ cross-over study was employed. After one tablet was orally administered, blood was taken at predetermined time intervals and the concentration of fexofenadine in plasma was determined using a validated HPLC method with fluorescence detector. Two pharmacokinetic parameters, $AUC_t$ and $C_{max}$, were calculated and analyzed statistically for the evaluation of bioequivalence of the two products. Analysis of variance was carried out using logarithmically transformed parameter values. The 90% confidence intervals of $AUC_t$ and $C_{max}$ were $log\;0.822{\sim}log \;1.142$ and $log\;0.848{\sim}log\;1.172$, respectively. These values were within the acceptable bioequivalence intervals of log 0.8 to log 1.25. Thus, the criteria of the KFDA guidelines for the bioequivalence was satisfied, indicating that Hanmi Fexofenadine Hydrochloride Tablet is bioequivalent to Allegra Tablet.
