Detection and Excretion Profile of Retatrutide in Human Plasma and Urine by LC-HRMS: Implications for Antidoping Analysis

IF 1.8 3区化学 Q4 BIOCHEMICAL RESEARCH METHODS

Rapid Communications in Mass Spectrometry Pub Date : 2026-09-15 DOI:10.1002/rcm.70179

Gabriel Reis Alves Carneiro, Isabelle Karine da Costa Nunes, Gustavo Ramalho dos Santos Cardoso, Paola Façanha dos Santos, Monica Costa Padilha, Fábio César Sousa Nogueira, Henrique Marcelo Gualberto Pereira

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引用次数: 0

Abstract

Rationale

Retatrutide (LY3437943) is a novel long-acting triple incretin receptor agonist that targets the glucagon-like peptide-1 receptor (GLP-1R), glucose-dependent insulinotropic polypeptide receptor (GIPR), and glucagon receptor (GCGR). Its pronounced effects on body composition and metabolic health, combined with increasing off-label use among physically active populations, raise concerns about potential misuse in sport. Despite growing clinical interest and anecdotal reports about use among amateur athletes, information on the detection and elimination profile of retatrutide in humans remains unexplored.

Methods

A method based on liquid chromatography–high-resolution mass spectrometry (LC-HRMS) dedicated to monitor retatrutide was developed and validated in human plasma and urine in accordance with World Anti-Doping Agency (WADA) criteria. Detection was based on the [M + 3H]³⁺ precursor ion by targeted selected-ion monitoring (t-SIM), with confirmatory analysis via parallel reaction monitoring (PRM) of structurally diagnostic fragment ions. From four retatrutide users who self-administered 2 mg subcutaneously on Days 1 and 7, blood and urine samples were collected at predefined time points following self-administration.

Results

The method was proved fit-for-purpose regarding selectivity, reliability, robustness, and stability. Limits of detection (LOD) were evaluated using both empirical ≥ 95% detection rate criteria and sigmoidal logistic regression modeling, yielding 6.14 ng/mL in plasma and 2.44 ng/mL in urine. Neither intact retatrutide nor metabolite-derived signals were detected in urine samples throughout the entire collection period, despite systematic application of multiple extraction strategies. Plasma concentration–time profiles exhibited nonmonotonic behavior, consistent with prolonged subcutaneous absorption and depot-like release kinetics following repeated dosing.

Conclusion

These findings suggest that plasma represents the appropriate matrix for intact retatrutide detection compared with urine. The extended plasma detection window, approximately 56 days after the first dose, supports plasma-based testing as a suitable analytical strategy for this and related long-acting therapeutic peptides in antidoping testing context.

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用LC-HRMS检测人血浆和尿液中的利特鲁肽及其排泄特征：对反兴奋剂分析的意义

利特鲁肽（LY3437943）是一种新型长效三重胰高血糖素受体激动剂，靶向胰高血糖素样肽-1受体（GLP-1R）、葡萄糖依赖性胰岛素性多肽受体（GIPR）和胰高血糖素受体（GCGR）。它对身体成分和代谢健康的显著影响，加上在体力活动人群中越来越多的超说明书使用，引起了人们对运动中潜在滥用的担忧。尽管在业余运动员中使用利特鲁肽的临床兴趣和轶事报道越来越多，但在人类中检测和消除利特鲁肽的信息仍未被探索。方法根据世界反兴奋剂机构（WADA）的标准，建立了一种液相色谱-高分辨率质谱（LC-HRMS）监测人血浆和尿液中利特鲁肽的方法，并进行了验证。通过靶向选择离子监测（t-SIM）对[M + 3H]3+前体离子进行检测，并通过结构诊断片段离子的平行反应监测（PRM）进行验证性分析。4名利特鲁肽使用者在第1天和第7天自我皮下注射2mg，在自我给药后的预定时间点收集血液和尿液样本。结果该方法在选择性、可靠性、稳健性、稳定性等方面均符合要求。采用≥95%的经验检出率标准和s型logistic回归模型评估检出限（LOD），血浆中为6.14 ng/mL，尿液中为2.44 ng/mL。尽管系统地应用了多种提取策略，但在整个收集期间尿液样本中均未检测到完整的利特鲁肽或代谢物衍生信号。血浆浓度-时间谱表现出非单调行为，与重复给药后的长时间皮下吸收和仓库样释放动力学一致。结论与尿液相比，血浆是检测完整利特鲁肽的合适基质。延长的血浆检测窗口，大约在第一次给药后56天，支持基于血浆的检测作为一种合适的分析策略，用于这种和相关的长效治疗性肽的反兴奋剂检测。

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

Rapid Communications in Mass Spectrometry 化学-分析化学

CiteScore

4.10

自引率

5.00%

发文量

219

审稿时长

2.6 months

期刊介绍： Rapid Communications in Mass Spectrometry is a journal whose aim is the rapid publication of original research results and ideas on all aspects of the science of gas-phase ions; it covers all the associated scientific disciplines. There is no formal limit on paper length ("rapid" is not synonymous with "brief"), but papers should be of a length that is commensurate with the importance and complexity of the results being reported. Contributions may be theoretical or practical in nature; they may deal with methods, techniques and applications, or with the interpretation of results; they may cover any area in science that depends directly on measurements made upon gaseous ions or that is associated with such measurements.