Determination of temozolomide and its metabolite 5-aminoimidazole-4-carboxamide in plasma using UPLC-MS/MS: Implications for therapeutic drug monitoring with high-grade gliomas

IF 3.1 3区医学 Q2 CHEMISTRY, ANALYTICAL

Journal of pharmaceutical and biomedical analysis Pub Date : 2025-09-08 DOI:10.1016/j.jpba.2025.117144

Ning Zhang , Shengwei Shen , Chuanguang Han , Jinhui Qiu , Zhiwei Wang , Chenlin Shen , Shuai Song , Huihui Ma

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引用次数: 0

Abstract

Temozolomide (TMZ) combined with radiotherapy is the standard regimen for high-grade gliomas (HGG). TMZ exhibits linear pharmacokinetics and consistent blood-brain barrier penetration, metabolizing to equimolar 5-aminoimidazole-4-carboxamide (AIC) and methyl diazonium cation, forming the basis of the Two-Ratio Hypothesis (plasma-to-cerebrospinal fluid TMZ/AIC ratios) for therapeutic drug monitoring. We developed a validated ultra-performance liquid chromatography-tandem mass spectrometry method to quantify TMZ and AIC in HGG patients. Addressing polarity differences, TMZ was enriched by ethyl acetate liquid-liquid extraction while AIC underwent strong cation exchange SPE. This method demonstrated linearity (TMZ: 77.66–19,415 ng/mL, AIC: 5.00–2000 ng/mL; r² > 0.99), precision (intra-batch RSD ≤ 11.85 %, inter-batch RSD ≤10.23 %), accuracy (RE: −7.48 to 4.94 % for TMZ; −5.25 to 5.26 % for AIC), recovery (97.26–102.5 %), and stability compliant with FDA/Chinese Pharmacopoeia guidelines. Analysis of 46 plasma samples (37 patients) revealed higher dose-normalized TMZ peak concentrations (1-h post-dose) in concurrent chemoradiotherapy versus adjuvant chemotherapy (3.54 vs. 2.48 μg/mL, P < 0.05). Females showed 52.4 % greater TMZ exposure than males (3.55 vs. 2.33 μg/mL, P < 0.05), while AIC exhibited no statistically significant gender- or treatment-related variations. Gender-adjusted TMZ-AIC correlation was moderate (r_s= 0.540, P < 0.01). This study provides the first analytical validation of the Two-Ratio Hypothesis and reveals gender-dependent TMZ pharmacokinetics, supporting personalized neuro-oncology dosing.

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UPLC-MS/MS测定血浆中替莫唑胺及其代谢物5-氨基咪唑-4-羧酰胺：对高级别胶质瘤治疗药物监测的意义

替莫唑胺（TMZ）联合放疗是治疗高级别胶质瘤（HGG）的标准方案。TMZ表现出线性药代动力学和一致的血脑屏障穿透，代谢为等摩尔5-氨基咪唑-4-羧酰胺（AIC）和甲基重氮离子，形成治疗药物监测的双比假说（血浆与脑脊液TMZ/AIC比）的基础。我们建立了一种有效的超高效液相色谱-串联质谱法来定量HGG患者的TMZ和AIC。为了解决极性差异，TMZ采用乙酸乙酯液液萃取富集，AIC采用强阳离子交换SPE富集。该方法线性良好（TMZ: 77.66 ~ 19415 ng/mL, AIC: 5.00 ~ 2000 ng/mL; r²> 0.99），精密度（批内RSD≤11.85 %，批间RSD≤10.23 %），准确度（RE: TMZ:−7.48 ~ 4.94 %,AIC:−5.25 ~ 5.26 %），回收率（97.26 ~ 102.5 %），稳定性符合FDA/中国药典标准。46份血浆样本（37例）分析显示，同步放化疗与辅助化疗相比，剂量标准化TMZ峰浓度（给药后1小时）更高（3.54 vs 2.48 μg/mL, P <； 0.05）。女性的TMZ暴露比男性高52.4 % (3.55 vs. 2.33 μg/mL, P <； 0.05)，而AIC在性别或治疗相关的差异上没有统计学意义。性别校正TMZ-AIC相关性中等（rs= 0.540, P <； 0.01）。该研究首次对双比假说进行了分析验证，揭示了性别依赖的TMZ药代动力学，为个性化神经肿瘤给药提供了支持。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of pharmaceutical and biomedical analysis 医学-分析化学

CiteScore

6.70

自引率

5.90%

发文量

588

审稿时长

37 days

期刊介绍： This journal is an international medium directed towards the needs of academic, clinical, government and industrial analysis by publishing original research reports and critical reviews on pharmaceutical and biomedical analysis. It covers the interdisciplinary aspects of analysis in the pharmaceutical, biomedical and clinical sciences, including developments in analytical methodology, instrumentation, computation and interpretation. Submissions on novel applications focusing on drug purity and stability studies, pharmacokinetics, therapeutic monitoring, metabolic profiling; drug-related aspects of analytical biochemistry and forensic toxicology; quality assurance in the pharmaceutical industry are also welcome. Studies from areas of well established and poorly selective methods, such as UV-VIS spectrophotometry (including derivative and multi-wavelength measurements), basic electroanalytical (potentiometric, polarographic and voltammetric) methods, fluorimetry, flow-injection analysis, etc. are accepted for publication in exceptional cases only, if a unique and substantial advantage over presently known systems is demonstrated. The same applies to the assay of simple drug formulations by any kind of methods and the determination of drugs in biological samples based merely on spiked samples. Drug purity/stability studies should contain information on the structure elucidation of the impurities/degradants.