DETERMINATION OF THE DIHYDROPYRIDINE ARYLOXYPROPANOLAMINE COMPOUND Z6568 AND 4 METABOLITES IN PLASMA BY LIQUID-CHROMATOGRAPHY NEGATIVE-ION MASS-SPECTROMETRY

A sensitive and selective liquid chromatographic/mass spectrometric as say for the determination of the dihydropyridine aryloxypropanolamine compound Z6568 and four metabolites in plasma was developed and valida ted. Z6568 and the metabolites were isolated from plasma by a simple s olvent extraction procedure and separated by reversed-phase high-speed liquid chromatography combined with thermospray mass spectrometry. Fi lament ionization was used and the molecular negative ions were monito red. The analysis of spiked plasma demonstrated the good accuracy and precision of the assay with a detection limit of 0.5 ng ml(-1) for Z65 68. Data relative to the optimization of the mass spectrometric condit ions and the validation protocol are reported. The method has been use d for pharmacokinetic studies in laboratory animals.