Abstract
Terbinafine is a synthetic allylamine that is available in an oral formulation and is used at a dosage of 250mg/day. It is used as an active antifungal agent and inhibits the fungal enzyme squalene epoxidase, which leads to the accumulation of the sterol squalene, which is toxic to the organism. The purpose of the present study was to evaluate the bioequivalence of two terbinafine tablets, Lamisil (Novartis Korea Ltd.) and Terbinex (C-TRI Ltd.), according to the guidelines of Korea Food and Drug Administration (KFDA). Eighteen normal male volunteers, 26.00$\pm$2.57 year in age and 70.51$\pm$9.36 kg in body weight, were divided into two groups and a randomized 2${\times}$2 cross-over study was employed. After one tablet containing 125 mg of terbinafine was orally administered, blood was taken at predetermined time intervals and the concentrations of terbinafine in plasma were determined using HPLC with UV detector. Pharmacokinetic parameters such as AUC, $C_{max}$ and $T_{max}$ were calculated and ANOVA test was utilized for the statistical analysis of the parameters. The results showed that the differences in AUC, $C_{max}$ and $T_{max}$ between two tablets were －4.191％, 5.223％ and －25.720％, respectively when calculated against the Lamisil, tablet. The powers (1-$\beta$) for AUC, $C_{max}$ and $T_{max}$ were 81％, 87％ and below 60％, respectively. Minimum detectable differences(.il) at alpha=O.1 and 1-/3=0.8 were less than 20％ (e.g., 19.72％ and 17.77％ for AUC and $C_{max}$, respectively). But minimum detectable differences($\Delta$) at alpha=0.1 and 1-$\beta$=0.8 for $T_{max}$ were more than 20％ (e.g., 26.25％). The 90％ confidence intervals were within $\pm$20％ (e.g., －17.440∼9.06 and －6.713∼17.160 for AUC and $C_{max}$ respectively). But 90％ confidence intervals for $T_{max}$ were not within $\pm$20％ (e.g., －43.346∼8.083). Another ANOVA test was conducted for logarithmically transformed AUC and $C_{max}$. These results showed that there are no significant differences in AUC and $C_{max}$ between the two formulations: The differences between the formulations in these log transformed parameters were all for less than 20％ (e.g., －4.19％ and 5.22％ for AUC and $C_{max}$, respectively). The 90％ confidence intervals for the log transformed data were not the acceptance range of log 0.8 to log 1.25 in AUC but the acceptance range of log 0.8 to log 1.25 in $C_{max}$ (e.g., log 1.13∼log 1.50 and log 0.94-log 1.22 for AUC and $C_{max}$ respectively). The major parameters, AUC and $C_{max}$ met the criteria of KFDA for bioequivalence although $T_{max}$ did not meet the criteria of KFDA (1998 year) for bioequivalence, indicating that Onfran tablet is bioequivalent to Zofran tablet. But in another ANOVA test AUC did not meet the criteria of KFDA (2002) for bioequivalence but $C_{max}$ met the criteria of KFDA (2002 year) for bioequivalence.or bioequivalence.equivalence.equivalence.equivalence.
