title: The analysis of SK&F 94120, a novel inotropic agent, and its four metabolites by isolation on C18 AASP cassettes followed by high-performance liquid chromatography.
abstract: A selective and specific assay for SK&F 94120 [5-(4-acetamidophenyl)pyrazin-2(1H)-one] and its four metabolites in plasma has been developed. The method incorporates a single liquid-solid extraction step using C18 Analytichem Automated Sample Processor (AASP) cassettes. This is followed by successive elutions of the solid phase with two mobile phases of increasing acetonitrile content, by an AASP liquid chromatography module. A mobile phase containing 10% acetonitrile elutes a glucuronide metabolite from the cartridge which is then chromatographed and quantified intact. A second mobile phase, containing 20% acetonitrile, is then used to elute the unchanged drug and the three other metabolites from the same cartridge. The assay shows good accuracy and precision (less than 10% for all analytes) and is able to determine SK&F 94120 and its metabolites in plasma at concentrations between 0.05 and 1.00 mg l(-1).
authors.affiliation: Department of Drug Analysis, Smith Kline and French Research Ltd., The Frythe, Welwyn, Herts AL6 9AR, UK.
authors.forename: J C
authors.initials: JC
authors.lastname: Pearce
authors.forename: W J
authors.initials: WJ
authors.lastname: Leavens
authors.forename: J A
authors.initials: JA
authors.lastname: Jelly
authors.forename: K A
authors.initials: KA
authors.lastname: Fernandes
authors.forename: R D
authors.initials: RD
authors.lastname: McDowall