Postmortem distribution and redistribution of MDAI and 2-MAPB in blood and alternative matrices

Intoxication cases involving new psychoactive substances (NPS) provide several challenges for forensic toxicologists as data on pharmacodynamic and pharmacokinetic properties are lacking, especially on potency and toxicity. Furthermore, reference values and information on postmortem redistribution (PMR) do not exist so far for most NPS. A fatal case involving the amphetamine-derivatives MDAI (5,6-methylenedioxy-2-aminoindane) and 2-MAPB (1-(benzofuran-2-yl)-N-methylpropan-2-amine) was investigated at the Zurich Institute of Forensic Medicine. At admission at the institute approx. 11h after death (first time point, t1), femoral and heart blood (right ventricle) was collected using computed tomography (CT)-guided biopsy sampling. At autopsy (t2), samples from the same body regions as well as various tissue samples were collected manually. In addition, an antemortem blood sample collected 6h before death was available. MDAI and 2-MAPB were quantified using a validated LC-MS/MS method. A significant concentration decrease between the antemortem and the first peripheral postmortem blood sample was observed, which most probably can be explained by remaining metabolism and excretion within the last 6h prior to death. No significant concentration change was observed between the two postmortem heart blood and peripheral blood samples. Accordingly, MDAI and 2-MAPB did not seem to undergo relevant postmortem redistribution in peripheral and heart blood in the presented case. This is the first study on postmortem redistribution of the new psychoactive substances MDAI and 2-MAPB. However, more studies covering more cases are necessary to generate universal statements on the PMR with these two NPSs.