Analysis of MT-45, a Novel Synthetic Opioid, in Human Whole Blood by LC-MS-MS and its Identification in a Drug-Related Death.

MT-45 (1-cyclohexyl-4-(1,2-diphenylethyl)piperazine) is just one of the many novel psychoactive substances (NPS) to have reached the recreational drug market in the twenty-first century; it is however, one of the first designer opioids to achieve some degree of popularity, in a market currently dominated by synthetic cannabinoids and designer stimulants. A single fatality involving MT-45 and etizolam is described. A method for the quantitation of MT-45 in whole blood using liquid chromatography-tandem mass spectrometry was developed and validated. The linear range was determined to be 1.0-100 ng/mL with a detection limit of 1.0 ng/mL, and the method met the requirements for acceptable linearity, precision and accuracy. After analyzing the sample on dilution and by standard addition, the concentration of MT-45 in the decedent's blood was determined to be 520 ng/mL, consistent with other concentrations of MT-45 reported in drug-related fatalities. Etizolam was present at a concentration of 35 ng/mL. This case illustrates the importance of considering non-traditional drugs in unexplained apparent drug-related deaths.