Department of Pharmaceutical Analysis, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, China; Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, China.
Department of Pharmaceutical Analysis, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, China; College of Pharmacy and Chemistry, Dali University, Wanhua Road, Dali, 671000, China.
J Pharm Biomed Anal. 2018 Mar 20;151:145-150. doi: 10.1016/j.jpba.2017.12.052. Epub 2017 Dec 28.
As an orally active iron chelator, deferasirox forms its ion complexes in the prepared plasma samples and LC-MS mobile phase where ferric ion exists, and then comparing with the nominal concentration level, a lower detected concentration level of deferasirox would be obtained after LC-MS analysis, if no proper treatment was adopted. Meanwhile, the phenomenon would be observed that multiple repeat injections of the same deferasirox plasma sample in the same tube would show the lower and lower detected concentration levels of deferasirox, which caused by more and more ferric ions from the injection needle dissolved in the sample solution as multiple repeated injections. The addition of a proper concentration of EDTA in the mobile phase and the sample will competitively inhibit deferasirox from complexing with ferric ion, and prevent the decrease of deferasirox concentration. In this paper, an LC-MS/MS method was developed and validated for the determination of deferasirox in human plasma. To achieve the protein precipitation, the analytes were extracted from aliquots of 200 μL human plasma with acetonitrile. Chromatographic separation was performed on an ODS-C18 column with the mobile phase consisted of methanol and 0.1% formic acid containing 0.04 mM ethylenediamine tetraacetate dihydrate (EDTA) (80:20, v/v) at a flow rate of 0.5 mL/min. Deferasirox and the internal standard (IS, mifepristone) were detected using electrospray ionization in positive ion multiple reaction monitoring mode by monitoring the precursor-to-product ion transitions m/z 374.2 → 108.1 for deferasirox and m/z 430.1 → 372.2 for the IS. The method exhibited good linearity over the concentration range of 0.04-40 μg/mL for deferasirox. The method was successfully applied to a pharmacokinetic study in 10 Chinese healthy volunteers after oral administration of deferasirox.
作为一种口服铁螯合剂，地拉罗司在准备好的血浆样品和 LC-MS 流动相中形成其离子配合物，而在 LC-MS 分析中，如果没有采取适当的处理方法，则会得到地拉罗司的检测浓度水平低于名义浓度水平。同时，还会观察到这种现象，即同一管中多次重复注射相同的地拉罗司血浆样品会导致地拉罗司的检测浓度水平越来越低，这是由于随着多次重复注射，来自注射针的越来越多的三价铁离子溶解在样品溶液中。在流动相和样品中加入适当浓度的 EDTA 将竞争性地抑制地拉罗司与三价铁离子形成配合物，并防止地拉罗司浓度降低。本文开发并验证了一种 LC-MS/MS 方法，用于测定人血浆中的地拉罗司。为了实现蛋白质沉淀，分析物从 200μL 人血浆等分试样中用乙腈提取。采用 ODS-C18 柱进行色谱分离，流动相由甲醇和 0.1%甲酸组成，含有 0.04mM 乙二胺四乙酸二水合物（EDTA）（80:20，v/v），流速为 0.5mL/min。地拉罗司和内标（IS，米非司酮）通过监测正离子多反应监测模式下的母离子-产物离子跃迁 m/z 374.2→108.1 进行检测，用于地拉罗司，m/z 430.1→372.2 用于 IS。该方法在地拉罗司浓度范围为 0.04-40μg/mL 时表现出良好的线性关系。该方法成功应用于 10 名中国健康志愿者口服地拉罗司后的药代动力学研究。
