Determination of biological equivalence of two atenolol preparations.

In healthy volunteers (n = 8), the biological equivalence of the two oral atenolol preparations was investigated. Atenolol concentration was assessed by HPLC. Drug and internal standard were isolated by adsorption with active charcoal. Chromatography was performed on RP-18 column (10 mu) with mobile phase of 0.015 mol/l KH2PO4/acetonitrile 70:30. The flow rate of the mobile phase was 1.5 ml/min. UV detector operated at the wave length of 225 nm. The sensitivity of the method was 25 micrograms/l and variation coefficients within the assay were less than 10% in the therapeutic concentration range. Biological half-life was on the average 3.8 h, absorption half-life 0.8 h, and the peak concentration time 2.5 h. Both preparations have been found bioequivalent.