title: A cocktail approach for assessing the in vitro activity of human cytochrome P450s: an overview of current methodologies.
abstract: An assessment of cytochrome P450 (CYP) enzyme activity is essential for characterizing the phase I metabolism of biological systems or to evaluate the inhibition/induction properties of xenobiotics. CYPs have generally been investigated individually by single probes, and metabolite formation has been monitored by liquid chromatography-mass spectrometry (LC-MS). To increase the throughput, many probes have been applied to assess multiple CYP activities simultaneously within a single experiment. This strategy is called the cocktail approach, and it has already been reviewed for in vivo applications, but never for in vitro ones. This review focuses for the first time on an in vitro cocktail approach, and it references the most notable articles on this topic. The advantages and limitations of applying cocktails for the in vitro activity assessment of major human CYPs, namely, CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and subfamily CYP3A, are discussed. This article considers the probe reaction selections for each CYP according to regulatory recommendations, probe metabolic properties (i.e., specificity and turnover), probe concentrations and analytical sensitivity, but it also highlights a challenge specific to cocktail design, which is probe-probe interaction. The last part of the review reports some methodologies for incubating these cocktails and discusses some important issues regarding the incubation time, enzyme concentrations and sample preparation.
authors.affiliation: School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Boulevard d'Yvoy 20, 1211 Geneva 4, Switzerland.
authors.forename: Dany
authors.initials: D
authors.lastname: Spaggiari
authors.affiliation: School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Boulevard d'Yvoy 20, 1211 Geneva 4, Switzerland.
authors.forename: Laurent
authors.initials: L
authors.lastname: Geiser
authors.affiliation: School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Boulevard d'Yvoy 20, 1211 Geneva 4, Switzerland.
authors.forename: Youssef
authors.initials: Y
authors.lastname: Daali
authors.affiliation: School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Boulevard d'Yvoy 20, 1211 Geneva 4, Switzerland. Electronic address: serge.rudaz@unige.ch.
authors.forename: Serge
authors.initials: S
authors.lastname: Rudaz
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013379:Substrate Specificity
chemical_list: D003577:Cytochrome P-450 Enzyme System
keywords: CYP phenotyping; Cocktail; Drug–drug interactions; Human liver microsomes; In vitro methodology