Methotrexate (MTX), a folate antagonist, is the anchor drug used to treat several diseases. Therapeutic effects are attributed to intracellular levels of various methotrexate conjugates that are present in the cell as polyglutamates (MTX‐Glu). The present study was conducted to develop a new liquid chromatography‐electrospray ionization‐tandem mass spectrometry (LC‐ESI‐MS/MS)‐based assay to separately quantitate the MTX‐Glu in hair cells, red blood cells, and serum using internal standards. Sample preparation consisted of extraction with an organic solution followed by solid‐phase extraction. The presented methodology was applied for the analysis of methotrexate and its polyglutamates in hair cells, red blood cells, and serum obtained from clinical patients. The developed LC‐ESI‐MS/MS method for the quantitative measurement of MTX‐Glu was both sensitive and precise within the clinically relevant range. This method is possibly be superior with respect to sensitivity, selectivity, and speed than all previously described approaches and can be easily applied in routine clinical tests owing to the combination of a simple pretreatment process with robust LC‐MS/MS.

中文翻译：

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使用高效液相色谱三重四极杆质谱 (LC-MS/MS) 检测分析头发和血浆样品中的甲氨蝶呤 (MTX) 和代谢物

甲氨蝶呤 (MTX) 是一种叶酸拮抗剂，是用于治疗多种疾病的锚定药物。治疗效果归因于细胞内以聚谷氨酸盐 (MTX-Glu) 形式存在的各种甲氨蝶呤偶联物的细胞内水平。本研究旨在开发一种新的基于液相色谱-电喷雾电离-串联质谱 (LC-ESI-MS/MS) 的检测方法，以使用内标分别定量毛细胞、红细胞和血清中的 MTX-Glu . 样品制备包括用有机溶液萃取，然后进行固相萃取。所提出的方法用于分析毛细胞、红细胞和临床患者血清中的甲氨蝶呤及其聚谷氨酸盐。开发的用于 MTX-Glu 定量测量的 LC-ESI-MS/MS 方法在临床相关范围内既灵敏又精确。该方法在灵敏度、选择性和速度方面可能优于所有先前描述的方法，并且由于将简单的预处理过程与稳定的 LC-MS/MS 相结合，可以轻松应用于常规临床测试。