Sammanfattning: New psychoactive substances (NPS) are drugs of abuse, designed to mimic traditional drugs, often evading existing drug laws, creating legal ambiguity and complicating enforcement strategies. NPS acts by activating target proteins such as opioid, cannabinoid receptor 1 (CB1), or serotonin receptors. Their unpredictable potency and limited toxicological data make NPS a global health concern. This thesis presents an in-depth pharmacological investigation of prevalent and/or toxic NPS, with a focus on their metabolic pathways and receptor interactions. Moreover, structure-activity relationships for closely related NPS analogs is presented. For the metabolism studies, in vitro drug incubation with either human primary hepatocytes or human liver microsomes was performed. Samples were analyzed with liquid chromatography high resolution or tandem mass spectrometry. Receptor activation was measured by the Aequoscreen luminescence assay. Detailed analysis of alicyclic fentanyl analogs revealed that ring size considerably influences both hepatic metabolism and μ-opioid receptor activity where the 4- or 3-membered ring fentanyl analogs show high potency and full agonist profiles, while 7- or 6- membered ring variants are less potent and partial agonists. Moreover, cyclopropylfentanyl metabolites retain μ-opioid activity, except for the detoxifying nor-metabolite. 60 NPS and their metabolites were screened across CB1, 5-HT1A, 5-HT2A, and μ-opioid receptors uncovered diverse on-target and off-target interactions, highlighting the complexity of their pharmacological profiles. Phase I metabolites of indole/indazole, pentyl/5F-pentyl synthetic cannabinoids (SC) were found to retain CB1 agonist activity. In silico modeling offered mechanistic insights into ligand-receptor interaction. Additionally, study V provides the first direct evidence of reactive epoxide metabolite formation from MDMB-4en-PICA and MMB-4en-PICA, raising concerns about potential cytotoxicity.The thesis thus combines NPS market analysis, in vitro metabolic profiling, including reactive metabolite formations, receptor pharmacodynamics, and in silico molecular dynamics to study NPS effects and toxicity. Findings, including potency data, provide valuable tools for detection, risk assessment, and harm-reduction strategies.
Pharmacology and Toxicity of New Psychoactive Substances : In vitro metabolism and receptor activation
