Bioavailability of atenolol formulations

AbstractIn this comparative bioavailability study two tablet formulations of atenolol (sales and clinical trial) were compared with an oral solution. Twelve healthy adult male volunteers received, on a cross‐over basis, on three separate occasions, 100 mg oral dose of the three formulations of atenolol. Bioavailability was based on concentrations of atenolol in whole blood and urine. The atenolol blood levels peaked at approximately 3 h after dosing, with individual values ranging from 0·21 to 0·92 μg ml−1 (a four‐fold difference), with all three formulations. Three‐fold variations among subjects occurred in the areas under the curve (AUC) and urinary recoveries. The average elimination half‐life of atenolol was between 6 and 7 h for all three formulations. Some statistically significant differences were observed between the tablets and the aqueous solution: the AUC (∞) and mean peak blood concentrations were significantly greater with the U.K. sales tablet than the solution, and the mean concentrations in the blood at certain specified times after administration were significantly greater with the two tablet formulations than the solution. The profiles of absorption and excretion of the two tablet formulations were similar.No adverse reactions were encountered in this study and all subjects completed the study without incident.