In recent years, the emergence of the novel designer benzodiazepine 4ʹ-chloro deschloroalprazolam has presented a new challenge for forensic laboratories by interfering with the identification and quantitation of alprazolam. As an isomer of alprazolam, 4ʹ-chloro deschloroalprazolam has similar physicochemical properties and can be misidentified in casework samples as alprazolam without a specific method to differentiate the two analytes. Starting in late 2021, the Houston Forensic Science Center (HFSC) received toxicological and seized drug evidence indicating the presence of 4ʹ-chloro deschloroalprazolam. An interference study was performed to supplement the laboratory’s validated benzodiazepines method for toxicological samples to differentiate alprazolam from 4ʹ-chloro deschloroalprazolam. This study showed that while the isomers could not be chromatographically resolved using the current method, they could be differentiated based on their retention times relative to the internal standard, alprazolam-d5. Based on these findings, the HFSC toxicology laboratory reports test results as “unsuitable for analysis due to an interference” if a suspected alprazolam peak elutes before the alprazolam-d5 peak, even if all identification and quantification criteria (e.g., retention time) were acceptable. Additionally, the seized drug and toxicology laboratories re-evaluated previously analyzed alprazolam-positive casework to determine if suspected 4ʹ-chloro deschloroalprazolam had been misidentified as alprazolam. This report presents three cases: one case with toxicological evidence indicating the presence of both 4ʹ-chloro deschloroalprazolam and alprazolam, and two cases with both seized drug material and toxicology evidence indicating the presence of 4ʹchloro deschloroalprazolam with no detected alprazolam.

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新型设计苯二氮卓4′-氯去氯阿普唑仑对阿普唑仑毒理学分析的干扰及查获毒品DUID案例

近年来，新型苯二氮卓类4′-氯代去氯阿普唑仑的出现，干扰了阿普唑仑的鉴定和定量，给法医实验室带来了新的挑战。作为阿普唑仑的异构体，4′-氯去氯阿普唑仑具有相似的理化性质，如果没有特定的方法来区分这两种分析物，在案例样品中可能会被误认为是阿普唑仑。从 2021 年底开始，休斯顿法医科学中心 (HFSC) 收到了毒理学和查获的药物证据，表明存在 4ʹ-氯去氯阿普唑仑。进行了一项干扰研究，以补充实验室验证的苯二氮卓类毒理学样品方法，以区分阿普唑仑和 4ʹ-氯去氯阿普唑仑。这项研究表明，虽然使用当前方法无法对异构体进行色谱分离，但可以根据其相对于内标阿普唑仑-d5 的保留时间来区分异构体。根据这些发现，如果可疑的阿普唑仑峰在阿普唑仑-d5 峰之前洗脱，即使所有鉴定和定量标准（例如保留时间）均可接受，HFSC 毒理学实验室也会将测试结果报告为“由于干扰而不适合分析” 。此外，被查获的药物和毒理学实验室重新评估了之前分析的阿普唑仑阳性病例，以确定可疑的 4′-氯去氯阿普唑仑是否被误认为是阿普唑仑。本报告介绍了三起案件：一起案件的毒理学证据表明存在 4'-氯代去氯阿普唑仑和阿普唑仑；两起案件的缉获原料和毒理学证据均表明存在 4'氯去氯阿普唑仑，但未检出阿普唑仑。