ABSTRACT
BACKGROUND: Dihydropyrimidine dehydrogenase (DPD) gene polymorphism may lead to severe toxicity with 5-fluorouracil (5-FU), a major anticancer drug extensively used in clinical oncology. Drug monitoring combined with early detection of patients at risk would enable timely dose adaptation so as to maintain drug concentrations within a therapeutic window. However, the best method to identify such patients remains to be determined. OBJECTIVE: The aim of this study was to develop a rapid and simple high-performance liquid chromatographic (HPLC) method for estimating uracil/dihydrouracil (U/UH2) ratio in plasma, as an index of DPD status, and for assaying 5-FU as part of drug level monitoring. METHOD: Assay of 5-FU, and U/UH2 detection were performed on a HPLC system equipped with UV detector. Analytes were separated at room temperature using a 5 microm particles, 25 cm RP-18 X-Terra column. The mobile-phase consisted of a KH(2)PO(4) salt solution (0.05 m) + 0.1% triethylamine (TEA) pumped at 0.4 mL/min. Detection of 5-FU and 5-bromouracil were performed at 254 nm; U and UH2 elution was monitored at 210 nm. RESULTS: The method was sensitive and specific for assaying 5-FU within the 5-500 ng/mL concentration range, which covers exposure levels currently met in clinical practice. The method was simple, and relatively cheap, and rapid, with an analytical run time of about 30 min. Data from a patient with 5-FU toxicity suggest that the method was capable of identifying DPD metabolic phenotype in cancer patients, based on measurement of plasma U/UH2 ratio. CONCLUSION: The method described should be suitable both for detecting patients at high risk of 5-FU toxicity, and for drug level monitoring during chemotherapy.
Subject(s)
Antimetabolites, Antineoplastic/blood , Antineoplastic Agents/metabolism , Chromatography, High Pressure Liquid/methods , Dihydrouracil Dehydrogenase (NADP)/metabolism , Fluorouracil/blood , Uracil/analogs & derivatives , Uracil/blood , Antimetabolites, Antineoplastic/adverse effects , Antimetabolites, Antineoplastic/pharmacokinetics , Dihydrouracil Dehydrogenase (NADP)/genetics , Female , Fluorouracil/adverse effects , Fluorouracil/pharmacokinetics , Humans , Middle Aged , Polymorphism, GeneticABSTRACT
A new rapid and sensitive high-performance liquid chromatographic method for analysis of docetaxel (Taxotere) in human plasma was developed and validated. After adding an internal standard (paclitaxel, Taxol), plasma was extracted following a simple liquid-liquid extraction with diethyl ether. Extraction efficiency averaged 95% for docetaxel. Separation was performed using a Nucleosil (C18) 5 microm column, monitored at 227 nm. The isocratic mobile phase consisted of acetonitrile-acetate buffer, pH 5-tetrahydrofuran (45:50:5, v/v) pumped at a flow-rate of 1.8 ml/min. The limit of quantification for docetaxel in plasma was 12.5 ng/ml. Retention times for docetaxel and paclitaxel were 7.7 and 9 min, respectively. Standard curves were linear over a range of 25-1,000 ng/ml. This new method is rapid since it does not require time-consuming extraction procedures, or complex chromatographic conditions. This rapidity, along with the lack of chromatographic interferences with various other drugs likely to be administered to the cancer patients (pain killers, corticoids, antiemetics drugs) make this method suitable for daily routine analysis of Taxotere, a major anticancer drug extensively used in clinical oncology.
Subject(s)
Antineoplastic Agents, Phytogenic/blood , Chromatography, High Pressure Liquid/methods , Paclitaxel/analogs & derivatives , Paclitaxel/blood , Taxoids , Antineoplastic Agents, Phytogenic/pharmacokinetics , Docetaxel , Humans , Paclitaxel/pharmacokinetics , Reproducibility of Results , Sensitivity and Specificity , Spectrophotometry, UltravioletABSTRACT
A new, rapid and sensitive high-performance liquid chromatographic method for the analysis of paclitaxel (Taxol) in human plasma and urine was developed and validated. After addition of an internal standard, paclitaxel was extracted from plasma or urine by a liquid-liquid extraction using diethyl ether. Extraction efficiency averaged 90%. Chromatography was performed isocratically on a reversed-phase column monitored at 227 nm. Retention times were 7.7 and 6.7 min for paclitaxel and docetaxel, respectively, and the assay was linear in the range 25-1000 ng/ml. The limits of quantification for paclitaxel were 25 and 40 ng/ml in plasma and urine, respectively. The assay was shown to be suitable for pharmacokinetic studies of children involved in a phase I clinical trial.
