title: Enantiospecific determination of nimodipine in human plasma by liquid chromatography-tandem mass spectrometry.
abstract: A direct enantiospecific HPLC assay using tandem mass spectrometric (MS-MS) detection via pneumatically-assisted electrospray has been developed for the determination of the calcium antagonist nimodipine in human plasma. By the addition of ammonium acetate (2 mM) to the purely organic eluent ethanol-n-heptane (20:80, v/v) charged species (M+NH4+) were producible by electrospray ionization at sufficient sensitivity. Routine determination of nimodipine enantiomers in human plasma in the working range of 0.5-75 microgram/l plasma for each isomer with an accuracy < or = +/- 10% and a precision of about 10% (20% close to the limit of quantification) was possible. This was comparable to the available LC-GC-MS assay, however, the time required for routine analysis of ca. 150 unknowns could be reduced from 4 weeks to 1 week.
authors.affiliation: Clinical Pharmacology International Bayer AG, Wuppertal, Germany.
authors.forename: W M
authors.initials: WM
authors.lastname: Mück
mesh_terms: D000085:Acetates; D002121:Calcium Channel Blockers / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods* / Q000706:statistics & numerical data; D009553:Nimodipine / Q000097:blood* / Q000737:chemistry; D012680:Sensitivity and Specificity; D013237:Stereoisomerism
chemical_list: D000085:Acetates; D002121:Calcium Channel Blockers; D009553:Nimodipine; C018824:ammonium acetate