HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ASSAY FOR THE DERIVATIZED ENANTIOMERS OF ATENOLOL IN WHOLE-BLOOD

A stereospecific high-performance liquid chromatographic (HPLC) method for the analysis of atenolol in human whole blood has been developed. The analytes were extracted from alkalinized plasma with ethyl acetate and derivatized with (-)-menthyl chloroformate (MCF). The resulting diastereomers were separated on a Hypersil ODS column with acetonitrile/water/methanol (43/32/25, V:V:V) as mobile phase and detected by fluorescence (230/305nm). Retention times for the diastereomeric derivatives of S(-)- and R(+)- atenolol were 9.8 and 11.0 minutes, respectively, with a resolution greater than 1.5. Standard curves were linear from 25.0 to 400 ng/mL for each enantiomer and exhibited correlation coefficients of 0.9975 or better (n = 6). Inter-assay variability was less than 7.5% for each enantiomer. Furthermore, the assay was suitable for measuring the concentrations of S(-)- and R(+)-atenolol in human whole blood after a single 100 mg oral dose of the racemate.