title: Gas chromatography/mass spectrometric study of non-commercial C-4-substituted 1,4-dihydropyridines and their oxidized derivatives.
abstract: A gas chromatography/mass spectrometry (GC/MS) method for the qualitative and quantitative determination of the calcium-channel antagonists C-4-substituted 1,4-dihydropyridines, and their corresponding N-ethyl derivatives, is presented. Also, the electrochemical oxidation and the reactivity of the compounds with alkyl radicals derived from 2,2'-azobis-(2-amidinopropane) were monitored by GC/MS. Mass spectral fragmentation patterns for the C-4-substituted 1,4-dihydropy-ridine parent drugs were significantly different from those of their oxidation products, generated either by electrochemical oxidation or by reaction with alkyl radicals. However, for N-ethyl-1,4-dihydropyridine compounds it was not possible to detect the final products (pyridinium salts) using these experimental conditions.
authors.affiliation: Laboratory of Bioelectrochemistry, Faculty of Chemical and Pharmaceutical Sciences, University of Chile, P.O. Box 233, Santiago, Chile.
authors.forename: C
authors.initials: C
authors.lastname: López-Alarcón
authors.forename: J A
authors.initials: JA
authors.lastname: Squella
authors.forename: Luis J
authors.initials: LJ
authors.lastname: Núñez-Vergara
authors.forename: H
authors.initials: H
authors.lastname: Baez
authors.forename: Cristián
authors.initials: C
authors.lastname: Camargo
mesh_terms: D002121:Calcium Channel Blockers / Q000737:chemistry*; D004095:Dihydropyridines / Q000737:chemistry* / Q000378:metabolism*; D004572:Electrolysis; D008401:Gas Chromatography-Mass Spectrometry; D015394:Molecular Structure; D010084:Oxidation-Reduction
chemical_list: D002121:Calcium Channel Blockers; D004095:Dihydropyridines; C038806:1,4-dihydropyridine