High Performance Liquid Chromatographic Determination of the Optical Isomers of Arotinolol and AC 623, Its Main Metabolite, in Biological Samples

Abstract

Abstract Arotinolol and its main metabolite, AC 623, both antihypertensive agents with β blocking properties could be separated simultaneously into their two enantiomers and determined in plasma and urine using a solid phase extraction in presence of an internal standard and HPLC using a chiral counterion (Z-glycyl-L-proline) followed by fluorimetric detection. Extraction yields are satisfactory and reproducible. Calibration curves in plasma showed good linearity at levels from 75 to 3 75 ng/ml Arotinolol (97 % R (−) and 3 % S (+) and from 5 to 25 ng/ml AC 623 (80 % R (−) and 20% = S(+)). Absolute amounts of each enantiomer could be calculated from the plasma standard curves, whereas percentages of each enantiomer were estimated from spiked plasma and urine. Both enantiomers of Arotinolol or AC 623 gave similar analytical response. They could be related to total amounts of drugs dosed using non-chiral HPLC (10). Accuracy was estimated from plasma calibration curves (R. E. < 10 % for Arotinolol enantiomers...