[Simultaneous determination of the inhibitory potency of compounds on the activity of five cytochrome P-450 enzymes using a cocktail probe substrates method].
This study developed a method for simultaneously assessing the inhibitory potency of compounds on five major cytochrome P-450 ( CYP450) enzymes using a cocktail of probe substrates. A cocktail selective substrates consisting of the phenacetin (PN, CYP1A2), dextromethorphan (DM, CYP2D6), tolbutamide (TB, CYP2C9), omeprazole (OPZ, CYP2C19) and midazolam (MPZ, CYP3A4) was incubated with human liver microsomes. The concentrations of the substrate metabolites paracetamol, dextrorphan, 4-hydroxytolbutamide, 5-hydroxyomeprazole and 1'-hydroxymidazolam were determined by LC/MS/MS in a single assay sample. The method was validated by incubating known CYP inhibitors--alpha-naphthoflavone (ANF, CYP1A2), quinidine (QND, CYP2D6), sulfaphenazole (SUL, CYP2C9), fluconazole (FLU, CYP2C19) and ketoconazole (KET, CYP3A4) with the individual substrates and with the substrate cocktail. The IC50 values were then determined. The IC50s (micromol x L(-1)) were in good agreement with those obtained with individual substrates (alpha-naphthoflavone, 0.18 vs 0.26; quinidine, 0.058 5 vs 0.058 4; sulfaphenazole, 0.48 vs 0.45; fluconazol, 17.5 vs 11.4; ketoconazole, 0.22 vs 0.24) and with previously reported values in the literature. This cocktail probe substrate method can be utilized for the rapid simultaneous determination of the inhibition potential of compounds on the five CYP450 enzymes.
Gao
Zhi-Wei
ZW
Clinical Pharmacy Laboratory, Huashan Hospital, Fudan University, Shanghai 200040, China.
Shi
Xiao-Jin
XJ
Yu
Chen
C
Li
Shui-Jun
SJ
Zhong
Ming-Kang
MK
D002853:Chromatography, Liquid; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D020128:Inhibitory Concentration 50; D053719:Tandem Mass Spectrometry
D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors