Assadullahi T P, Dagli E, Warner J O
Department of Paediatrics, National Heart and Lung Institute, Brompton Hospital, London, U.K.
J Chromatogr. 1991 Apr 19;565(1-2):349-56. doi: 10.1016/0378-4347(91)80395-s.
Monitoring of low-dose methotrexate (MTX), as used in severe steroid-dependent asthma, requires a sensitive and reproducible technique which has hitherto not been available. A high-performance liquid chromatographic method for the determination of MTX in serum is reported. The method involves deproteinization with acetone followed by addition of butanol and diethyl ether. The percentage recovery with this method compared with others was high (90 versus 70%). The samples were chromatographed on a reversed-phase ODS column and monitored at 313 nm. The retention time for MTX was 14.7 min. Pharmacokinetics of MTX was studied in five patients (age 3-15 years) with severe asthma who received a weekly oral dose of 10 mg/m2 body surface area. Following administration, the serum disappearance was monophasic with a half-life of 5 h. A metabolite, 7-hydroxymethotrexate was detected in serum after 2 h and reached a maximum concentration after 6 h. This new method will facilitate monitoring of asthmatic patients on methotrexate and allow for dose response and toxicity studies to be conducted.
监测用于重度激素依赖型哮喘的低剂量甲氨蝶呤（MTX），需要一种灵敏且可重复的技术，而目前尚无此类技术。本文报道了一种用于测定血清中甲氨蝶呤的高效液相色谱法。该方法包括用丙酮进行蛋白沉淀，随后加入丁醇和乙醚。与其他方法相比，此方法的回收率较高（90%对70%）。样品在反相ODS柱上进行色谱分析，并在313 nm处进行监测。甲氨蝶呤的保留时间为14.7分钟。对5名重度哮喘患者（年龄3至15岁）进行了甲氨蝶呤的药代动力学研究，这些患者每周口服剂量为10 mg/m²体表面积。给药后，血清消除呈单相，半衰期为5小时。2小时后在血清中检测到一种代谢物7-羟基甲氨蝶呤，6小时后达到最大浓度。这种新方法将有助于监测接受甲氨蝶呤治疗的哮喘患者，并可进行剂量反应和毒性研究。
