Abstract
Metformin is an oral antihyperglycemic agent used in the therapy of noninsulin-dependent diabetes mellitus and does not cause hypoglycemia at the therapeutic dose. The purpose of the present study was to evaluate the bioequivalence of two metformin hydrochloride tablets, Glucophage tablet (DaeWoong Pharmaceutical Co., reference drug) and Dybis tablet (Shinpoong Pharmaceutical Co., test drug), according to the guidelines of Korea Food and Drug Administration(KFDA). Twenty-four normal volunteers, 26.6$\pm$4.01 years in age and 60.6$\pm$9.80 kg in body weight, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After one tablet containing 500 mg of metformin hydrochloride was orally administered, blood was taken at predetermined time intervals and the concentrations of metformin hydrochloride in serum were determined using HPLC with UV detector. The pharmacokinetic parameters such as AUCt, Cmax and Tmax were calculated and ANOVA test was utilized for the statistical analysis of the parameters. The results showed that the differences in AUCt, Cmax and Tmax between two products were -1.05％, -6.76％ and -4.51％, respectively, when calculated against the reference drug. The 90％ confidence intervals using logarithmically transformed data were within the acceptance range of log0.8$\leq$$\delta$$\leq$log1.25 (e.g., log0.9082$\leq$$\delta$$\leq$log1.0906 and log0.8188$\leq$$\delta$$\leq$log1.0392 for $AUC_{t}$ and $C_{max}$, respectively). The 90％ confidence intervals using untransformed data was within $\pm$20％ (e.g., -17.66％$\leq$$\delta$$\leq$8.63％ for $T_{max}$). All parameters met the criteria of KFDA for bioequivalence, indicating that Dybis tablets (Shinpoong Pharmaceutical Co.) is bioequivalent to Glucophage tablets (DaeWoong Pharmaceutical Co.).
