1. Analysis of caffeine and paraxanthine in human saliva with ultra-high-performance liquid chromatography for CYP1A2 phenotyping.
- Author
-
Jordan NY, Mimpen JY, van den Bogaard WJ, Flesch FM, van de Meent MH, and Torano JS
- Subjects
- Caffeine metabolism, Cytochrome P-450 CYP1A2 metabolism, Humans, Linear Models, Phenotype, Reproducibility of Results, Sensitivity and Specificity, Theophylline metabolism, Caffeine analysis, Chromatography, High Pressure Liquid methods, Cytochrome P-450 CYP1A2 classification, Saliva chemistry, Theophylline analysis
- Abstract
Cytochrome P450 1A2 (CYP1A2) plays an important role in drug metabolism. Caffeine (CAF) is converted into paraxanthine (PX) by this enzyme and is used as a xenobiotic substrate to determine the CYP1A2 phenotype in humans. A method for the quantification of CAF and PX in saliva was developed using liquid-liquid extraction with ethyl acetate and analysis with ultra-high-performance liquid chromatography. Peaks from CAF, PX and internal standard were resolved within 6min. The method was validated from 0.05 to 5μgmL(-1) CAF and 0.025-2.5μgmL(-1) PX. Inter- and intra-day accuracies ranged from 91.2 to 107.2% with precisions <13.5%. The limits of detection were 0.16 and 0.63 ngmL(-1) for PX and CAF, respectively. PX/CAF concentration ratios from volunteers were 0.26-1.09 with mean ratios of 0.78±0.26 and 0.38±0.10 for regular and light/non-coffee drinkers, respectively., (Copyright © 2015 Elsevier B.V. All rights reserved.)
- Published
- 2015
- Full Text
- View/download PDF