Abstract
Epinastine is an antiallergic drug effective for bronchial asthma, allergic rhinitis, urticaria and dermatitis. Epinastine is topically active, direct H1-receptor antagonist and an inhibitor of the release of histamine from the mast cell. The purpose of the present study was to evaluate the bioequivalence of two epinastine hydrochloride tablets, Alesion Tablet (Boehringer Ingelheim Korea Ltd.) and S-napine tablet 10 mg(Sam Chun Dang Pharm. Co., Ltd), according to the guidelines of the Korea Food and Drug Administration(KFDA). The release of epinastine from the two epinastine formulations in vitro was tested using KP VIII Apparatus II method with various dissolution media(pH 1.2, 4.0, 6.8 buffer solution and water). Twenty six healthy male subjects, $23.35{\pm}1.57$ years in age and $66.29{\pm}10.61kg$ in body weight, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After two tablets containing 20 mg as epinastine hydrochloride was orally administered, blood was taken at predetermined time intervals and the concentrations of epinastine in serum were determined using HPLC with UV detector. The dissolution profiles of two formulations were similar at all dissolution media. In addition, the pharmacokinetic parameters such as $AUC_t,\;C_{max}\;and\;T_{max}$ were calculated and ANOVA test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t.\;C_{max}$ and untransformed $T_{max}$. The results showed that the differences between two formulations based on the reference drug, Alesion tablet, were 1.50, 1.46 and -13.48% for $AUC_t,\;C_{max}\;and\;T_{max}$, respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log 0.8 to log 1.25(e.g., log 0.95$\sim$log 1.12 and log 0.93$\sim$log 1.10 for $AUC_t\;and\;C_{max}$, respectively). Thus, the criteria of the KFDA bioequivalence guideline were satisfied, indicating S-napine tablet 10 mg was bioequivalent to Alesion tablet.
