Development and validation of a fast and sensitive UPLC-MS/MS method for the quantification of six probe metabolites for the in vitro determination of cytochrome P450 activity

► The development of a UPLC-MS/MS method for in vitro CYP activity determination. ► A generic, fast gradient for detection of all metabolites. ► The method was fully validated for precision, accuracy and selectivity. ► Despite absolute matrix effects, no relative matrix effects were observed. ► Low activities in diseased liver samples were successfully detected.