Analysis of urinary caffeine metabolites by HPLC-DAD: the use of metabolic ratios to assess CYP1A2 enzyme activity.
An improved extraction procedure and a new RP-HPLC method were developed for selective and rapid analysis of caffeine and 14 of its metabolites in urine. Analytes were isolated by solid-phase extraction and separated on an Eclipse XDB-C18 column. Recoveries ranged between 83 and 99%. Precision, linearity and accuracy of the chromatographic method were found to be within required limits. Using this procedure, caffeine metabolic ratios were determined in 20 subjects with characteristic CYP1A2 activities, relatively to smoking habit and contraceptives intake. The method might be useful to point out induction and inhibition of CYP1A2 activity.
Caubet
Marie-Sophie
MS
Chaire Médicaments, Grossesse et Allaitement, Faculté de Pharmacie, Centre de Recherche de l'Hôpital Sainte-Justine, Recherche de l'Hôpital Sainte-Justine, Montreal, Canada. mscaubet@justine.umontreal.ca
Elbast
Walid
W
Dubuc
Marie-Claude
MC
Brazier
Jean-Louis
JL
D000328:Adult; D002110:Caffeine / Q000032:analysis / Q000378:metabolism* / Q000652:urine; D002247:Carbon Isotopes; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D019388:Cytochrome P-450 CYP1A2 / Q000032:analysis* / Q000096:biosynthesis; D005260:Female; D006801:Humans; D008099:Liver / Q000378:metabolism; D008297:Male; D008956:Models, Chemical; D015203:Reproducibility of Results
D002247:Carbon Isotopes; D002110:Caffeine; D019388:Cytochrome P-450 CYP1A2