Abstract
Finasteride $[N-(1, 1-dimethylethyl)-3-oxo-4-aza-5{\alpha}-androst-1-ene-17{\beta}-carboxamide]$ is a 4-aza-3-oxosteroidal inhibitor of human $5{\alpha}-reductase$. The purpose of the present study was to evaluate the bioequivalence of two finasteride tablets, $Proscar^{\circledR}$ (MSD Korea Ltd.) and Procare (Hana Pharm. Co., Ltd.), according to the guidelines of the Korea Food and Drug Administration (KFDA). The release of finasteride from the two finasteride 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, $23.7\;{\pm}\;2.24$ years in age and $67.2\;{\pm}\;8.55\;kg$ in body weight, were divided into two groups and a randomized $2\;{\time}\;2$ cross-over study was employed. After two tablets containing 5 mg as finasteride was orally administered, blood samples were taken at predetermined time intervals and the concentrations of finasteride in serum were determined using HPLC with UV detector. The dissolution profiles of two formulations were similar in all tested dissolution media. 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, $Proscar^{\circledR}$, were 6.39, 4.65 and -13.9% 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 0.800 to log 1.25 $(e.g.,\;log\;0.990{\sim}log\;1.14\;and\;log\;0.977{\sim}log\;1.13 for\;AUC_t\;and\;C_{max},\;respectively)$. Thus, the criteria of the KFDA bioequivalence guideline were satisfied, indicating Procare tablet was bioequivalent to $Proscar^{\circledR}$ tablet.
