Starting in 2019, an emerging class of novel opioids causing public health concern was benzimidazole opioids, also known as “nitazenes”. Two nitazenes, isotonitazene and metonitazene, were detected in postmortem samples received at the NYC Office of the Chief Medical Examiner. A protein precipitation extraction procedure was developed and validated for metonitazene and isotonitazene using 50 μL of blood, serum, liver, brain, and urine utilizing liquid chromatography–tandem mass spectrometry (LC–MS-MS). The limit of detection for both analytes was 0.10 ng/mL in plasma, blood, and brain, and was 1.0 ng/mL for urine and liver. The developed method was applied to authentic casework in which isotonitazene was detected in 10 cases between 2021 and 2022, with femoral blood concentrations ranging from 0.11 to 12 ng/mL. Metonitazene was detected in four cases in 2022 with concentrations ranging from 0.10 to 1.5 ng/mL in femoral blood. All but one case had the presence of fentanyl and/or fentanyl analogs, and the next most commonly encountered analyte in these cases was xylazine. The manner of death was accidental for all cases with a detected nitazene, and all but one case was attributed to mixed drug intoxications. None of the cases reported the identified nitazene compound as the sole intoxicant responsible for death. The opioid crisis continues to tear apart communities throughout the world, including New York City. Continued research and communication regarding these drugs helps to fight this crisis.

中文翻译：

---

血浆、血液、尿液、肝脏和大脑中美托氮卓和异托氮卓定量分析方法的验证及其在纽约市真实尸检案例中的应用

从 2019 年开始，一类新兴的新型阿片类药物引起了公众健康担忧，即苯并咪唑阿片类药物，也称为“硝氮类药物”。纽约市首席法医办公室收到的尸检样本中检测到了两种硝氮酮，即异硝氮酮和美托氮酮。利用液相色谱-串联质谱 (LC-MS-MS)，使用 50 μL 血液、血清、肝脏、大脑和尿液，开发并验证了甲托氮卓和异托氮嗪的蛋白质沉淀提取程序。血浆、血液和脑中两种分析物的检测限均为 0.10 ng/mL，尿液和肝脏中的检测限为 1.0 ng/mL。所开发的方法应用于真实案例研究，其中 2021 年至 2022 年间在 10 例病例中检测到异渗氮酮，股骨血液浓度范围为 0.11 至 12 ng/mL。2022 年，在 4 例病例中检测到美托氮平，股血中的浓度范围为 0.10 至 1.5 ng/mL。除一个案例外，所有案例均存在芬太尼和/或芬太尼类似物，这些案例中下一个最常见的分析物是赛拉嗪。所有检出硝氮酮的病例都是意外死亡，除一例外，所有病例均归因于混合药物中毒。没有一个病例报告所确定的硝氮化合物是导致死亡的唯一麻醉剂。阿片类药物危机继续撕裂世界各地的社区，包括纽约市。关于这些药物的持续研究和交流有助于应对这场危机。