title: Determination of a 'GW cocktail' of cytochrome P450 probe substrates and their metabolites in plasma and urine using automated solid phase extraction and fast gradient liquid chromatography tandem mass spectrometry.
abstract: A mass spectrometry based method for the simultaneous determination of an in vivo Greenford-Ware or 'GW cocktail' of CYP450 probe substrates and their metabolites in both human plasma and urine is described. The probe substrates, caffeine, diclofenac, mephenytoin, debrisoquine, chlorzoxazone and midazolam, together with their respective metabolites and stable isotope labelled internal standards, are simultaneously extracted from the biological matrix using solid phase extraction in 96-well microtitre plate format, automated by means of a custom built Zymark robotic system. The extracts are analysed by fast gradient high performance liquid chromatography (HPLC) with detection by tandem mass spectrometry (MS/MS) using thermally and pneumatically assisted electrospray ionisation in both positive and negative ion modes and selected reaction monitoring. The methods are specific, accurate and precise with intra- and inter-assay precision (%CV) of less than 15% for all analytes.
authors.affiliation: Department of International Bioanalysis, Glaxo Wellcome R&D, Park Road, Ware, Herts SG12 0DP, UK.
authors.forename: R J
authors.initials: RJ
authors.lastname: Scott
authors.forename: J
authors.initials: J
authors.lastname: Palmer
authors.forename: I A
authors.initials: IA
authors.lastname: Lewis
authors.forename: S
authors.initials: S
authors.lastname: Pleasance
mesh_terms: D001331:Automation; D002110:Caffeine / Q000031:analogs & derivatives / Q000097:blood* / Q000493:pharmacokinetics / Q000652:urine; D002753:Chlorzoxazone / Q000031:analogs & derivatives / Q000097:blood* / Q000493:pharmacokinetics / Q000652:urine; D002849:Chromatography, Gas / Q000379:methods; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D003647:Debrisoquin / Q000031:analogs & derivatives / Q000097:blood* / Q000493:pharmacokinetics / Q000652:urine; D004008:Diclofenac / Q000031:analogs & derivatives / Q000097:blood* / Q000493:pharmacokinetics / Q000652:urine; D005966:Glucuronidase; D006801:Humans; D007202:Indicators and Reagents; D008874:Midazolam / Q000031:analogs & derivatives / Q000097:blood* / Q000493:pharmacokinetics / Q000652:urine; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013379:Substrate Specificity; D013806:Theophylline / Q000097:blood* / Q000493:pharmacokinetics / Q000652:urine
chemical_list: D007202:Indicators and Reagents; D004008:Diclofenac; D002110:Caffeine; D003577:Cytochrome P-450 Enzyme System; D013806:Theophylline; D005966:Glucuronidase; D002753:Chlorzoxazone; C021183:1,7-dimethylxanthine; D008874:Midazolam; D003647:Debrisoquin