Emara Samy, Masujima Tsutomu, Zarad Walaa, Kamal Maha, El-Bagary Ramzia
Pharmaceutical Chemistry Department, Faculty of Pharmacy, Misr International University, Km 28 Ismailia Road, Cairo, Egypt.
Analytical Molecular Medicine and Devices Laboratory, Hiroshima University, Graduate School of Biomedical Sciences, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
J Pharm Anal. 2013 Feb;3(1):28-35. doi: 10.1016/j.jpha.2012.10.003. Epub 2012 Oct 26.
A new simple, sensitive and precise green analytical procedure using an automated packed-reactor derivatization technique coupled with on-line solid-phase enrichment (SPEn) has been developed and evaluated to determine trace levels of methotrexate (MTX). The method was based on injection of MTX into a flowing stream of phosphate buffer (0.04 M, pH 3.4), carried through the packed oxidant reactor of Cerium (IV) trihydroxyhydroperoxide for oxidative cleavage of the drug into highly fluorescent product, 2,4-diaminopteridine-6-carboxylic acid, followed by SPEn on a head of short ODS column (10 mm×4.6 mm i.d., 5 μm particle size). The flow rate was 0.25 mL/min and packed reactor temperature was 40 °C. The trapped product was back-flush eluted from the ODS column to the detector by column-switching with an environmentally friendly mobile phase consisting of ethanol and phosphate buffer (0.04 M, pH 3.4) in the ratio of 5:95 (v/v). The eluent was monitored at emission and excitation wavelengths of 460 and 360 nm, respectively. The calibration curve was linear over the concentration range of 1.25-50 ng/mL with a detection limit of 0.08 ng/mL. The method was successfully applied to determine MTX in pharmaceutical formulations with mean percentage recovery ranging from 99.48 to 99.60.
一种新的简单、灵敏且精确的绿色分析方法已被开发并评估，该方法采用自动填充反应器衍生技术与在线固相富集（SPEn）相结合来测定痕量甲氨蝶呤（MTX）。该方法基于将MTX注入到0.04 M、pH 3.4的磷酸盐缓冲液流动流中，流经铈（IV）三羟基氢过氧化物填充氧化反应器，将药物氧化裂解为高荧光产物2,4 - 二氨基蝶啶 - 6 - 羧酸，随后在短的ODS柱（内径10 mm×4.6 mm，粒径5 μm）前端进行SPEn。流速为0.25 mL/min，填充反应器温度为40℃。通过柱切换，用由乙醇和磷酸盐缓冲液（0.04 M，pH 3.4）按5:95（v/v）比例组成的环保流动相将捕集的产物从ODS柱反冲洗脱至检测器。分别在发射波长460 nm和激发波长360 nm处监测洗脱液。校准曲线在1.25 - 50 ng/mL浓度范围内呈线性，检测限为0.08 ng/mL。该方法成功应用于测定药物制剂中的MTX，平均回收率在99.48%至99.60%之间。
