Gas chromatographic-negative-ion chemical ionization mass spectrometric determination of a new dihydropyridine calcium antagonist (MPC-1304) and its metabolites in human plasma and urine

• Published in: Journal of chromatography Vol. 434; no. 1; p. 123
• Main Authors: Umeno, Y, Matsushima, E, Maniwa, M, Marunaka, T
• Format: Journal Article
• Language: English
• Published: Netherlands 1988
• Subjects: Animals; Anions; Calcium Channel Blockers - blood; Calcium Channel Blockers - metabolism; Calcium Channel Blockers - urine; Chemical Phenomena; Chemistry; Dihydropyridines - blood; Dihydropyridines - metabolism; Dihydropyridines - urine; Dogs; Gas Chromatography-Mass Spectrometry; Humans
• DOI: 10.1016/0378-4347(88)80067-7

A gas chromatographic-negative-ion chemical ionization mass spectrometric method was developed for the determination of a new calcium antagonist, (+/-)-methyl 2-oxopropyl 1,4-dihydro-2,6-dimethyl-4-(2-nitrophenyl)-3,5-pyridinedicarboxylate, and its metabolites in plasma and urine. The sample was extracted with n-hexane-diethyl ether. The dried organic layer was subjected to acetylation: the aqueous layer was acidified and extracted with ethyl acetate, and after the ethyl acetate extract was dried the resulting residue was subjected to methylation. Aliquots of each reactant solution were injected into the gas chromatograph-mass spectrometer, equipped with a chemical ionization source and negative-ion monitoring mode, and analysed by the selected-ion monitoring method using deuterium-labelled internal standards. Detection was limited to 0.02-0.05 ng/ml of plasma and urine for each metabolite. A precise and sensitive assay for the determination of a new dihydropyridine calcium antagonist and its metabolites in plasma and urine was thus established.