Toxicological investigation of forensic cases related to the designer drug 3,4-methylenedioxypyrovalerone (MDPV): Detection, quantification and studies on human metabolism by GC-MS

3,4-methylenedioxypyrovalerone (MDPV) is a synthetic cathinone belonging to the class of a-pyrrolidinophenones that become increasingly popular as a designer psychostimulant. Here, we report a comprehensive collection of MDPV exposure with quantitative serum level confirmation in Germany. During the years 2014-2016, we could proof consumption of MDPV in 23 cases where urine and blood samples were submitted to our laboratory by the police of Lower Saxony. Most of the samples underwent systematic toxicological analysis by gas chromatography-mass spectrometry (GC-MS), where MDPV could be detected in urine and/or serum samples. The determined concentrations of MDPV in serum showed a high variability, ranging from traces (< 10 ng/mL) up to 576 ng/mL with a mean concentration of 118 ng/mL and median of 47 ng/mL. The majority of MDPV users were men (87%) and the age ranged from 23 to 49 years (mean 35.9, median 37 years). For most of the analytically confirmed MDPV cases we could prove co-consumption of other psychotropic drugs with frequent occurrence of opiates and cannabinoids in 22% of the cases, followed by benzodiazepines and cocaine in 17%. Analysis of urine samples by GC-MS disclosed the presence of MDPV and its metabolites 2'-oxo-MDPV, demethylenyl-MDPV, demethylenyl-methyl-MDPV, demethylenyl-oxo-MDPV, demethylenyl-methyloxo- MDPV and demethylenyl-methyl-N, N-bisdealkyl-MDPV. The metabolite pattern substantiates previous suggestions for principle metabolic pathways of MDPV in humans. (C) 2017 Elsevier B.V. All rights reserved.