Detection of main metabolites of XLR-11 and its thermal degradation product in human hepatoma HepaRG cells and human urine.

The metabolism of (1-(5-fluoropentyl)-1H-indol-3-yl)(2,2,3,3-tetramethylcyclopropyl)methanone (XLR-11), a novel synthetic cannabinoid, was studied using a HepaRG cell culture. The HepaRG cells were incubated with the drug for 48 hours and the metabolites were extracted from the culture medium by liquid-liquid extraction. The extract was analyzed by liquid chromatography/mass spectrometry to detect the metabolites. N-(5-Hydroxypentyl) metabolite and N-pentanoic acid metabolite were identified in the culture medium of XLR-11, and several other metabolites, presumably formed by oxidation of the first two metabolites and XLR-11, were detected. The extract of an XLR-11 user's urine was also analyzed; however, the metabolites detected in the urine were different from XLR-11 metabolites in the medium. A metabolic experiment with the thermal degradation product of XLR-11, XLR-11 degradant, using HepaRG cells revealed that the urinary metabolites were almost identical to the XLR-11 degradant metabolites. These findings suggest that most of the XLR-11 was degraded by heating when the user smoked the herbal product containing XLR-11.