Development of an LC-QTOF MS Method for Determination of Urinary 6beta-Hydroxycortisol-to-Cortisol Ratio as an Indicator of CYP3A4 Activity

摘要

A new LC-MS method based on UPLC-QTOF MS was developed for reliable quantitation of urinary 6beta-HC and cortisol. LC-MS conditions were optimized to have significantly enhanced analytical sensitivity, and a dynamic range of ca. 700 was achieved for the two compounds, LLE was shown to be superior to SPE for sample preparation by minimizing the matrix effect. This validated method is being used as an alternative approach to measuring urinary 6beta-HC/cortisol ratio as an indicator of CYP3A4 activity in a cohort of pre-menstrual women at different phases of the menstrual cycle.