Background: `Herbal mixtures` containing synthetic cannabinoid receptor agonists
(SCRAs) are promoted as legal alternative to marihuana and are easily available via the Internet. Keeping
analytical methods for the detection of these SCRAs up-to-date is a continuous challenge for clinicians
and toxicologists due to the high diversity of the chemical structures and the frequent emergence
of new compounds. Since many SCRAs are extensively metabolized, analytical methods used for urine
testing require previous identification of the major metabolites of each compound.
Objective: The aim of this study was to identify the in vivo major metabolites of nine SCRAs (AM-
694, AM-2201, JWH-007, JWH-019, JWH-203, JWH-307, MAM-2201, UR-144, XLR-11) for unambiguous
detection of a drug uptake by analysis of urine samples.
Method: Positive urine samples from patients of hospitals, detoxification and therapy centers as well as
forensic-psychiatric clinics were analyzed by means of liquid chromatography-tandem mass spectrometry
(LC-MS/MS) and liquid chromatography-quadrupole time-of-flight mass spectrometry (LCqToF-
MS) for investigation of the major in vivo metabolites.
Results: For all investigated SCRAs, monohydroxylation, dihydroxylation and/or formation of the Nhexanoic/
pentanoic acid metabolites were among the most abundant metabolites detected in human urine
samples. Substitution of the fluorine atom was observed to be an important metabolic reaction for compounds
carrying an N-(5-fluoropentyl) side chain. N-Dealkylated metabolites were not detected in vivo.
Conclusion: The investigated metabolites facilitate the reliable detection of drug uptake by analysis of
urine samples. For distinction between uptake of the fluorinated and the non-fluorinated analogs, the
N-(4-hydroxypentyl) metabolite of the non-fluorinated analog was identified as a useful analytical target
and consumption marker.