Bioequivalence Study of Hydrocortisone Tablets while Secretion of Endogenous Cortisol Suppressed

The purpose of this study was to evaluate the bioequivalence of the test (Daewoo Hydrocortisone 10 mg, Daewoo Pharm. Co., Busan, Korea) and reference (Jenapharm Hydrocortisone 10 mg, JayTech Biogen, Seoul, Korea) hydrocortisone tablets. Twenty-four healthy male Korean volunteers were divided into two groups with a randomized $2{\times}2$ cross-over design. In order to suppress the endogenous cortisol secretion, a single oral dose of Dexamethasone (4 mg) was administered 10 hr prior to hydrocortisone administration. Blood samples were withdrawn for 10 hr at the predetermined intervals after a single oral dose of hydrocortisone (20 mg). The serum concentration of hydrocortisone was analyzed by HPLC/UV using a column switching method after liquid-liquid extraction process. The pharmacokinetic parameters ($AUC_{0{\sim}10hr}$, $C_{max}$, and $T_{max}$) of the test and reference hydrocortisone tablets were determined while the secretion of endogenous cortisol was being suppressed. The pharmacokinetic parameters of the test tablet were not statistically different from those of the reference tablet at ex value was 0.05. The 90% confidence intervals for the average ratio (test/reference) of $AUC_{0{\sim}10hr}$ and $C_{max}$ were within the Korea Food and Drug Administration acceptance range of 0.80-1.25 ($0.89{\sim}0.99$ and $0.86{\sim}0.99$ for $AUC_{0{\sim}10hr}$ and $C_{max}$, respectively). Therefore it was concluded that the test tablet, Daewoo Hydrocortisone tablet was bioequivalent to the reference tablet, Jenapharm Hydrocortisone tablet.