Separation and quantitation of (R)‐ and (S)‐atenolol in human plasma and urine using an α 1 ‐AGP column

A method for the determination of (R)‐ and (S)‐atenolol in human plasma and urine is described. The enantiomers of atenolol are extracted into dichloromethane containing 3% heptafluorobutanol followed by acetylation with acetic anhydride at 60°C for 2 h. The acetylated enantiomers were separated on a chiral α 1 ‐AGP column. Quantitation was performed using fluorescence detection. A phosphate buffer pH 7.1 (0.01 M phosphate) containing 0.25% (v/v) acetonitrile was used as mobile phase. The described procedure allows the detection of less than 6 ng of each enantiomer in 1 ml plasma. The relative standard deviation is 4.4% at 30 ng/ml of each enantiomer in plasma. The plasma concentration of (R)‐ and (S)‐ atenolol did not differ significantly in two subjects who received a single tablet of racemic atenolol. The R/S ratio of atenolol in urine was ∼ 1.