Evaluation of agonistic activity of fluorinated and nonfluorinated fentanyl analogs on μ-opioid receptor using a cell-based assay system

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 Nphenyl 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.