Analysis of nine drugs and their cytochrome P450-specific probe metabolites from urine by liquid chromatography–tandem mass spectrometry utilizing sub 2 μm particle size column

An LC/MS/MS method was developed for the analysis of twelve cytochrome P450 (CYP)-specific probe metabolites and their nine parent drugs from human urine. CYP-specific metabolites of melatonin (CYP1A2), nicotine (CYP2A6), bupropion (CYP2B6), repaglinide (CYP2C8), losartan (CYP2C9), omeprazole (CYP2C19 and CYP3A4), dextromethorphan (CYP2D6), chlorzoxazone (CYP2E1) and midazolam (CYP3A4) were all analyzed using the same LC/MS/MS method with a single analytical run, either after a one-at-a-time dose or cocktail-type dosing of the parent drugs. Ultra performance liquid chromatography (UPLC) with a 1.7 μm particle size column was utilized, providing 1.5–3-fold increase in sensitivity, decrease of analysis time to one third and clearly better chromatographic peak shapes when comparing it with the method using traditional high performance liquid chromatography for the same metabolites. In addition, the method was applied for the analysis of the metabolites from human urine samples collected at multiple time points after single and N-in-one dosing of each of the drugs, showing that the use of both the analytical method and these probe metabolites as CYP-specific markers is feasible in in vivo drug–drug interaction or phenotyping studies.