Liquid chromatographic analysis and preliminary pharmacokinetics of methotrexate in cancer patients co-treated with docetaxel

摘要

A new HPLC method has been developed for the quantitative determination of methotrexate (MTX) and its 7-hydroxyl metabolite in human plasma. Samples were purified by protein precipitation with acetone and methanol, and a sample clean-up with a mixture of n-butanol and diethyl ether. The analytes were separated on an RP Inertsil ODS-80A column and eluted in a solvent system containing 5% (v/v) tetrahydrofuran in water (pH 2.0).UV absorption measurement was performed at 313 nm,and the detector response was linear in a concentration range of 10-10 000 ng/ml. The lower limit of quantitation of MTX was 10 ng/ml using 1 ml sample aliquots. Values for accuracy and (within-run and between-run) precision were between 95.5-11% and 3.69-11.0%,respectively,at four concentrations analyzed in quintuplicate on four separate occasions. The assay was applied to study the effects of docetaxel co-administration on the pharmacokinetics and metabolism of MTX in cancer parients.