Lau Timothy, LeBlanc Raquel, Botch-Jones Sabra
Department of Anatomy and Neurobiology, Boston University School of Medicine, Biomedical Forensic Sciences, 72 E. Concord Street, R806, Boston, MA 02118, USA.
J Anal Toxicol. 2018 Mar 1;42(2):88-98. doi: 10.1093/jat/bkx090.
While circumventing legislative controls, synthetic piperazines are encountered as "legal" alternatives to ecstasy. Unforeseeable challenges may delay quantitative analysis of these compounds in biological fluids. Enzymatic reactions, matrix interferences and limited knowledge of analyte stability further complicate interpretation of calculated concentrations. The objective of this study was to investigate the stability of synthetic piperazines in human blood under various storage conditions over time. All samples were prepared by spiking certified reference standards (Cayman Chemical, MI, U.S.A.) of eight synthetic piperazine into certified drug-free human whole blood (UTAK Laboratories, Inc., CA, U.S.A.) independently at 1000 ng/mL as well as mixtures containing all tested piperazines in this study. Samples were stored at room temperature (~20°C), 4°C and -20°C for 1, 3, 6, 9 and 12 months in dark sealed containers. Solid phase extraction (SPE) was performed using mixed-mode copolymeric cartridges (Clean Screen®, UCT Inc., PA, U.S.A.). Analytes were assessed on their degrees of degradation using a Shimadzu Ultra-Fast Liquid Chromatograph with SCIEX 4000 Q-Trap Electrospray Ionization Tandem Mass Spectrometer (UFLC-ESI-MS/MS) in positive ionization mode. Of the two categories, benzyl piperazines were more stable than phenyl piperazines under all storage conditions, in which 1-(4-methylbenzyl)-piperazine (MBZP) had more than 70% (769-1,047 ng/mL) remaining after 12 months. 1-(4-methoxyphenyl)-piperazine (MeOPP) was not detected under room and refrigerated temperatures after 6 months and was the least stable. Matrix interferences and drug-drug interaction were observed. Storing samples at room temperature should be avoided due to detrimental impacts on stability of piperazine compounds. For backlog situations, case samples suspected to contain synthetic piperazines should be kept frozen or refrigerated even for time periods as short as 30 days for optimal result. Phenyl piperazines stored for more than 6 months showed analyte degradation and loss of parent compounds after extended storage regardless of storage conditions.
在规避立法管控的过程中，合成哌嗪作为摇头丸的“合法”替代品被发现。不可预见的挑战可能会延迟对生物流体中这些化合物的定量分析。酶促反应、基质干扰以及对分析物稳定性的了解有限，进一步使计算浓度的解释变得复杂。本研究的目的是调查合成哌嗪在人血中于不同储存条件下随时间的稳定性。所有样品均通过将八种合成哌嗪的认证参考标准品（美国密歇根州开曼化学公司）以1000 ng/mL的浓度分别加入认证的无药人全血（美国加利福尼亚州UTAK实验室公司）以及本研究中包含所有测试哌嗪的混合物中制备而成。样品在黑暗密封容器中于室温（约20°C）、4°C和 -20°C下储存1、3、6、9和12个月。使用混合模式共聚柱（美国宾夕法尼亚州UCT公司的Clean Screen®）进行固相萃取（SPE）。使用配备SCIEX 4000 Q - Trap电喷雾电离串联质谱仪的岛津超快速液相色谱仪在正离子模式下评估分析物的降解程度。在所有储存条件下，苄基哌嗪比苯基哌嗪更稳定，其中1 - （4 - 甲基苄基） - 哌嗪（MBZP）在12个月后仍有超过70%（769 - 1047 ng/mL）残留。6个月后，在室温和冷藏温度下均未检测到1 - （4 - 甲氧基苯基） - 哌嗪（MeOPP），其稳定性最差。观察到了基质干扰和药物 - 药物相互作用。由于对哌嗪化合物稳定性有不利影响，应避免在室温下储存样品。对于积压情况，怀疑含有合成哌嗪的病例样品即使仅保存30天，也应冷冻或冷藏以获得最佳结果。无论储存条件如何，储存超过6个月的苯基哌嗪在长时间储存后均显示出分析物降解和母体化合物损失。
