Experimental and Clinical Pharmacology Unit, Centro di Riferimento Oncologico di Aviano (CRO) IRCCS, Aviano, Italy.
Doctoral School in Nanotechnology, University of Trieste, Trieste, Italy.
PLoS One. 2019 Nov 19;14(11):e0225225. doi: 10.1371/journal.pone.0225225. eCollection 2019.
The introduction of imatinib, an oral tyrosine kinase inhibitor, as first-line standard therapy in patients with unresectable, metastatic, or recurrent gastro-intestinal stromal tumor (GIST), strongly improved their treatment outcomes. However, therapeutic drug monitoring (TDM) is recommended for this drug due to the large inter-individual variability in plasma concentration when standard dose is administered. A Cmin higher than 760 ng/mL was associated with a longer progression free survival. Thus, a LC-MS/MS method has been developed and fully validated to quantify imatinib and its active metabolite, norimatinib, in finger-prick dried blood spot (DBS). The influence of hematocrit, sample homogeneity, and spot size and the correlation between finger-prick and venous DBS measurements were also assessed. The method showed a good linearity (R2 > 0,996) between 50-7500 ng/mL for imatinib and 10-1500 ng/mL for norimatinib. Analytes were extracted from DBS samples by simply adding to 3 mm-discs 150 μL of acidified methanol containing IMA-D8. The collected extract was then injected on a LC Nexera system in-house configured for the on-line cleanup, coupled with an API-4000 QT. The chromatographic separation was conducted on a Synergi Fusion-RP column (4 μm, 2x50 mm) while the trapping column was a POROS R1/20 (20 μm, 2x30 mm). The total run time was 8.5 min. DBSs stored at room temperature in plastic envelopes containing a silica-gel drying bag were stable up to 16 months. The proposed method was applied to 67 clinical samples, showing a good correlation between patients' finger-prick DBS and plasma concentrations, measured by the reference LC-MS/MS method, internally validated. Imatinib and norimatinib concentrations found in finger-prick DBS were adjusted by hematocrit or by an experimental correction factor to estimate the corresponding plasma measurements. At the best of our knowledge, the proposed LC-MS/MS method is the first analytical assay to measure imatinib and norimatinib in DBS samples.
伊马替尼（一种口服酪氨酸激酶抑制剂）的引入作为不可切除、转移性或复发性胃肠间质瘤（GIST）患者的一线标准治疗方法，极大地改善了他们的治疗效果。然而，由于标准剂量给药时个体间血浆浓度差异较大，建议对该药物进行治疗药物监测（TDM）。Cmin 高于 760ng/mL 与无进展生存期延长相关。因此，开发并充分验证了一种 LC-MS/MS 方法，用于定量指尖干血斑（DBS）中的伊马替尼及其活性代谢物尼马替尼。还评估了血细胞比容、样品均一性、斑点大小的影响以及指尖 DBS 和静脉 DBS 测量之间的相关性。该方法显示伊马替尼在 50-7500ng/mL 之间以及尼马替尼在 10-1500ng/mL 之间具有良好的线性关系（R2>0.996）。分析物通过向 3mm 圆盘加入 150μL 酸化甲醇中包含 IMA-D8 从 DBS 样品中提取。收集的提取物然后在内部配置的用于在线净化的 LC Nexera 系统上注入，与 API-4000 QT 耦合。色谱分离在 Synergi Fusion-RP 柱（4μm，2x50mm）上进行，而捕集柱为 POROS R1/20（20μm，2x30mm）。总运行时间为 8.5 分钟。储存在塑料信封中并含有硅胶干燥袋的室温下的 DBS 稳定长达 16 个月。所提出的方法应用于 67 个临床样本，通过内部验证的参考 LC-MS/MS 方法，显示患者指尖 DBS 和血浆浓度之间具有良好的相关性。通过血细胞比容或实验校正因子调整指尖 DBS 中的伊马替尼和尼马替尼浓度，以估计相应的血浆测量值。据我们所知，所提出的 LC-MS/MS 方法是第一个用于测量 DBS 样本中伊马替尼和尼马替尼的分析测定方法。
