Determination of Caffeine and its Metabolites in Saliva and Urine as a Measure of CYP1A2 Metabolic Activity
| Authors | |
|---|---|
| Year of publication | 2016 |
| Type | Article in Periodical |
| Magazine / Source | Current Pharmaceutical Analysis |
| MU Faculty or unit | |
| Citation | |
| Doi | http://dx.doi.org/10.2174/1573412912666151119212608 |
| Field | Pharmacology and pharmaceutical chemistry |
| Keywords | caffeine; CYP1A2; saliva; urine; phenotyping; metabolic ratio |
| Description | Objective: The aim of this work was to develop a new, simple, rapid, sensitive and reproducible RP-HPLC method for the determination of caffeine, 1,7 dimethylxanthine, 1,7-dimethyluric acid, 5- acetylamino-6-formylamino-3-methyluracil, 5-acetylamino-6-amino-3-methyluracil, 1-methylxanthine, and 1-methyluric acid in human urine and saliva as a method of determining the metabolic activity of the human enzyme CYP1A2. Methods: A Luna C18(2) (150 × 4.6 mm i.d.) analytical column was used for the separation. The mobile phase consisted of sodium acetate trihydrate (pH 5.0) and methanol 85:15 (v/v). The flow rate was maintained at 0.8 mL/min. The absorbance of the eluent was monitored at 263 nm (5-acetylamino-6-amino-3- methyluracil), 285 nm (5-acetylamino-6-formylamino-3-methyluracil, 1,7-dimethyluric acid, 1- methyluric acid), 272 nm (caffeine, 1,7 dimethylxanthine) and 268 nm (1-methylxanthine). Acetaminophen as an internal standard was used to ensure the precision and accuracy of this method, and it was monitored at 245 nm. Results: All compounds, including the internal standard, were eluted within 18 min. Analytes were extracted by liquid-liquid extraction. Limits of quantitation varied from 7.2 to 74.2 microg/L for individual analytes in saliva and from 8.4 to 82.4 microg/L in urine. Conslusion: This method may become a useful alternative to urine caffeine metabolic ratio measurement with respect to CYP1A2 metabolic activity assessment in clinical practice. |
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