Detection of the recently emerged synthetic cannabinoid 4F-MDMB-BINACA in "legal high" products and human urine specimens.

Synthetic cannabinoids (SCs) remain one of the largest groups of new psychoactive substances (NPS) on the European drug market. Although the number of new derivatives occurring on the market has dropped in the last two years, newly emerging NPS still represent a challenge for laboratories performing forensic drug analysis in biological matrices. The newly emerged SC 4F-MDMB-BINACA has been reported by several law enforcement agencies in Europe and the USA since November 2018. This work aimed at revealing urinary markers to prove uptake of 4F-MDMB-BINACA and differentiate from the use of structurally similar SCs. Phase-I metabolites detected in human urine specimens were confirmed by phase-I metabolites generated in vitro using a pooled human liver microsomes (pHLM) assay. Seized materials and test-purchased "legal high" products were analyzed by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-quadrupole-time-of-flight-mass spectrometry (LC-qToF-MS). Human urine specimens and pHLM assay extracts were measured with liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) and confirmed by LC-qToF-MS. In January 2019, the Institute of Legal Medicine in Erlangen (Germany) identified 4F-MDMB-BINACA in three herbal blends. During the same time period, the described SC was identified in a research chemical purchased online. Investigation of phase-I metabolism led to the metabolites M10 (ester hydrolysis) and M11 (ester hydrolysis and dehydrogenation) as reliable urinary markers. Widespread distribution on the German drug market was proven by analysis of urine samples from abstinence control programs and by frequent detection of 4F-MDMB-BINACA in "herbal blends" and "'research chemicals" purchased via the Internet.