Comparative pharmacokinetics and bioequivalence of two 50 mg atenolol tablet formulations in healthy Korean male volunteers.

Atenolol is a selective β1 receptor antagonist that is available as a racemic mixture. The objective of this study was to compare the pharmacokinetics and evaluate the bioequivalence of 50 mg atenolol test and reference formulations in 24 healthy Korean male volunteers.This study was a single-dose, randomized, open-label, 2 period crossover study. 24 healthy Korean male volunteers randomly received 50 mg of either test or reference atenolol formulations in a 2×2 crossover study. There was a 1 week washout period between doses. The area under the curve (AUC)0-24 h and Cmax of 50 mg atenolol were the primary criteria for evaluation of bioequivalence.The mean ± standard deviation (SD) values of the Cmax, Tmax, AUC0-24 h, AUC0-∞, ke, and t1/2 of the test and reference formulations were 268.4 (78.96) and 256.9 (79.34), 2.750 (0.9555) and 3.104 (1.053), 1 981 (729.2) and 1 872 (604.8), 2228 (697.1) and 2 187 (628.5), 0.1332 (0.02748) and 0.1421 (0.04223), 5.419 (1.110) and 5.442 (2.357), respectively. The 90% confidence intervals for AUC0-24 h and Cmax were 0.9037-1.166 and 0.9169-1.1987, respectively. These results were within the accepted bioequivalence range of 0.80-1.25, which satisfied the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration guidelines. In conclusion, the findings of this study indicate that the 2 formulations of 50 mg atenolol that were tested are bioequivalent. Therefore, these formulations may be prescribed interchangeably.