There has been a surge in the presence and use of cannabinoids since the federal legalization of hemp (Agricultural Improvement Act of 2018). This increase is attributed not only to the use of ∆9-tetrahydrocannabinol (∆9-THC) and cannabidiol (CBD), the most abundant phytocannabinoid components of cannabis and hemp, respectively, but with the use of many other emerging THC analogs. Structurally, these analogs are similar to ∆9-THC. Urine specimens for drug analysis are often collected offsite and transported to a laboratory for analysis. Screening assays are usually the first step in urine drug testing. These assays are usually qualitative and automated, which for negative specimens, reduces cost and reporting time. The stability of ∆9-THC and its metabolites has been known for some time, however the stability of emerging analogs has not been elucidated, therefore assuming equivalent storage stability can be erroneous. Previous work assessed the cross-reactivity of ∆8-THC and its major metabolites, the ∆1°-THC chiral analogs, and the chiral 11-COOH-HHC analogs. Stability was assessed for each analyte at a concentration two times greater than the analytes determined decision point. Samples were prepared in drug-free urine at three different pHs (4.5, 7, and 9) and stored at three different temperatures (4°C, 20°C, and 45°C) in triplicate. Samples were analyzed utilizing the LZI Cannabinoids (cTHC) Enzyme Immunoassay cannabinoid screening kit calibrated at the 25 ng/mL cutoff. Overall, the cannabinoid analogs produced diminishing instrument responses depending on pH and temperature. The parent analogs were not detected after a single day at 45°C regardless of pH. In general, carboxylic acid analogs at the acidic pH (4.5) produced diminished instrument responses when compared to their counterparts stored at neutral (7) and basic (9) pH. The time, storage temperature, and pH of urine specimens may affect the screening results of specimens collected for cannabinoid drug screening.

中文翻译：

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尿液中新兴大麻素类似物（Delta-8 THC 及其代谢物、Delta-10 THC 和羧基-HHC）的分析前稳定性

自大麻联邦合法化（2018 年农业改进法案）以来，大麻素的存在和使用激增。这种增加不仅归因于大麻和大麻中最丰富的植物大麻素成分 Δ9-四氢大麻酚 (Δ9-THC) 和大麻二酚 (CBD) 的使用，还归因于许多其他新兴 THC 类似物的使用。在结构上，这些类似物与 Δ9-THC 相似。用于药物分析的尿液样本通常在场外收集并运送到实验室进行分析。筛查测定通常是尿液药物检测的第一步。这些检测通常是定性的和自动化的，对于阴性样本来说，可以降低成本和报告时间。Δ9-THC 及其代谢物的稳定性已知已有一段时间，但新兴类似物的稳定性尚未阐明，因此假设等效的储存稳定性可能是错误的。先前的工作评估了 Δ8-THC 及其主要代谢物、Δ1°-THC 手性类似物和手性 11-COOH-HHC 类似物的交叉反应性。以比分析物确定的决策点高两倍的浓度评估每种分析物的稳定性。样品在三种不同 pH 值（4.5、7 和 9）的无药尿液中制备，并在三种不同温度（4°C、20°C 和 45°C）下储存，一式三份。使用以 25 ng/mL 截止浓度校准的 LZI 大麻素 (cTHC) 酶免疫分析大麻素筛选试剂盒对样品进行分析。总体而言，大麻素类似物产生的仪器响应逐渐减弱，具体取决于 pH 值和温度。无论 pH 值如何，在 45°C 下放置一天后均未检测到母体类似物。一般来说，与储存在中性 (7) 和碱性 (9) pH 下的对应物相比，酸性 pH (4.5) 下的羧酸类似物产生的仪器响应减弱。尿液标本的时间、储存温度和 pH 值可能会影响大麻素药物筛查所采集标本的筛查结果。