HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC DETERMINATION OF OXODIPINE ENANTIOMERS, A NEW 1,4-DIHYDROPYRIDINE, APPLIED TO STEREOSELECTIVITY STUDIES IN MAN AND DOG

A specific and reproducible HPLC method using a Chiral-AGP column and UV detection was developed for the evaluation of the pharmacokinetic p rofile of oxodipine enantiomers in dog and man. Each enantiomer was de termined in plasma in the concentration range 1-400 ng/ml using the in ternal standard calibration method with linear regression analysis. Af ter extraction of oxodipine and the internal standard at alkaline pH w ith diethyl ether-n-hexane (50:50, v/v), this method permitted the det ermination of each enantiomer at levels down to 10 ng/ml in dog plasma and 25 ng/ml in human plasma with sufficient accuracy (relative error <11%, n = 6) and precision (coefficient of variation <16%, n = 6). Th e extracted plasma volume was 500 mu l and after evaporation of the or ganic phase, the dry residue was dissolved in 100 mu l of water-2-prop anol; an aliquot of 80 mu l was injected into the HPLC system.