title: Specific determination of urinary 6beta-hydroxycortisol and cortisol by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.
abstract: The urinary 6beta-hydroxycortisol to cortisol ratio is believed to be a noninvasive index of cytochrome P450 3A activity. For precise assessment of the ratio in human urine, we have developed a reversed-phase high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry method. The selective method was accurate and reproducible with intra- and inter-day precision of variation coefficients of less than 8%. The 6beta-hydroxycortisol to cortisol ratio ranged from 3.0 to 12.4 in healthy Japanese 24-h urine. With the recent popularization of LC-MS, our LC-MS method will be advantageous to detect human in vivo CYP3A activity for clinical investigation and routine measurement in various laboratories.
authors.affiliation: Department of Clinical Evaluation of Medicines and Therapeutics, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Ohno
authors.forename: I
authors.initials: I
authors.lastname: Yamaguchi
authors.forename: K
authors.initials: K
authors.lastname: Saiki
authors.forename: I
authors.initials: I
authors.lastname: Yamamoto
authors.forename: J
authors.initials: J
authors.lastname: Azuma
mesh_terms: D000328:Adult; D001274:Atmospheric Pressure; D002138:Calibration; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000031:analogs & derivatives / Q000652:urine*; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: C001380:6 beta-hydroxycortisol; D006854:Hydrocortisone