ABSTRACT
The agonistic activity of fluorinated and nonfluorinated fentanyl analogs on µ-opioid receptor was investigated using a cell-based assay system. Based on the activity, fentanyl analogs were ranked as follows: fentanyl > isobutyrylfentanyl ≈ butyrylfentanyl ≈ methoxyacetylfentanyl > acetylfentanyl. However, among the fentanyl analogs fluorinated on the N-phenyl ring, 2-fluoro analogs and 3-fluoro analogs showed the strongest and weakest activities, respectively. These results suggest that the 2-fluorinated isomers of fentanyl analogs are more likely to cause poisoning.
Subject(s)
Analgesics, Opioid/pharmacology , Fentanyl/pharmacology , Receptors, Opioid, mu/agonists , Animals , CHO Cells , Cricetulus , Drug Evaluation, Preclinical , Fentanyl/analogs & derivativesABSTRACT
The metabolism of butyrylfentanyl, a new designer drug, was investigated using fresh human hepatocytes isolated from a liver-humanized mouse model. In the culture medium of hepatocytes incubated with butyrylfentanyl, the desphenethylated metabolite (nor-butyrylfentanyl), ω-hydroxy-butyrylfentanyl, (ω-1)-hydroxy-butyrylfentanyl, 4'-hydroxy-butyrylfentanyl, ß-hydroxy-butyrylfentanyl, 4'-hydroxy-3'-methoxy-butyrylfentanyl, and ω-carboxy-fentanyl were identified as the metabolites of butyrylfentanyl. Each metabolite was definitively identified by comparing the analytical data with those of authentic standards. The amount of the main metabolite, nor-butyrylfentanyl, reached 37% of the initial amount of butyrylfentanyl at 48 h. ω-Hydroxy-butyrylfentanyl and (ω-1)-hydroxy-butyrylfentanyl, formed by hydroxylation at the N-butyryl group of butyrylfentanyl, were the second and third largest metabolites, respectively. The majority of 4'-hydroxy-butyrylfentanyl and 4'-hydroxy-3'-methoxy-butyrylfentanyl was considered to be conjugated. CYP reaction phenotyping for butyrylfentanyl using human liver microsomes and various anti-CYP antibodies revealed that CYP3A4 was involved in the formation of nor-butyrylfentanyl, (ω-1)-hydroxy-butyrylfentanyl, and ß-hydroxy-butyrylfentanyl. In contrast, CYP2D6 was involved in the formation of ω-hydroxy-butyrylfentanyl.
Subject(s)
Fentanyl/analogs & derivatives , Hepatocytes/metabolism , Illicit Drugs/metabolism , Cells, Cultured , Cytochrome P-450 CYP2D6/metabolism , Cytochrome P-450 CYP3A/metabolism , Fentanyl/metabolism , Humans , Microsomes, Liver/metabolism , Reference StandardsABSTRACT
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.