Characterization of novel nitazene recreational drugs: Insights into their risk potential from in vitro µ-opioid receptor assays and in vivo behavioral studies in mice

2-Benzylbenzimidazole derivatives or ‘nitazenes’ are increasingly present on the recreational drug market. Here, we report the synthesis and pharmacological characterization of 15 structurally diverse nitazenes that might be predicted to emerge or grow in popularity. This work expands the existing k...

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Main Authors: Marthe M. Vandeputte, Grant C. Glatfelter, Donna Walther, Nathan K. Layle, Danielle M. St. Germaine, István Ujváry, Donna M. Iula, Michael H. Baumann, Christophe P. Stove
Format: Article
Language:English
Published: Elsevier 2024-12-01
Series:Pharmacological Research
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Online Access:http://www.sciencedirect.com/science/article/pii/S1043661824004481
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author Marthe M. Vandeputte
Grant C. Glatfelter
Donna Walther
Nathan K. Layle
Danielle M. St. Germaine
István Ujváry
Donna M. Iula
Michael H. Baumann
Christophe P. Stove
author_facet Marthe M. Vandeputte
Grant C. Glatfelter
Donna Walther
Nathan K. Layle
Danielle M. St. Germaine
István Ujváry
Donna M. Iula
Michael H. Baumann
Christophe P. Stove
author_sort Marthe M. Vandeputte
collection DOAJ
description 2-Benzylbenzimidazole derivatives or ‘nitazenes’ are increasingly present on the recreational drug market. Here, we report the synthesis and pharmacological characterization of 15 structurally diverse nitazenes that might be predicted to emerge or grow in popularity. This work expands the existing knowledge about 2-benzylbenzimidazole structure-activity relationships (SARs), while also helping stakeholders (e.g., forensic toxicologists, clinicians, policymakers) in their risk assessment and preparedness for the potential next generation of nitazenes. In vitro µ-opioid receptor (MOR) affinity was determined via competition radioligand (3[H]DAMGO) binding assays in rat brain tissue. MOR activation (potency and efficacy) was studied by means of a cell-based β-arrestin 2 recruitment assay. For seven nitazenes, including etonitazene, opioid-like pharmacodynamic effects (antinociception, locomotor activity, body temperature changes) were evaluated after subcutaneous administration in male C57BL/6 J mice. The results showed that all nitazenes bound to MOR with nanomolar affinities, and the functional potency of several of them was comparable to or exceeded that of fentanyl. In vivo, dose-dependent effects were observed for antinociception, locomotor activity, and body temperature changes in mice. SAR insights included the high opioid-like activity of methionitazene, iso-butonitazene, sec-butonitazene, and the etonitazene analogues 1-ethyl-pyrrolidinylmethyl N-desalkyl etonitazene and ethylene etonitazene. The most potent analogue of the panel across all functional assays was α’-methyl etonitazene. Taken together, through critical pharmacological evaluation, this work provides a framework for strengthened preparedness and risk assessments of current and future nitazenes that have the potential to cause harm to users.
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spelling doaj-art-1e6ec420012c427cb9ccc61ca32e7ede2025-08-20T01:57:55ZengElsevierPharmacological Research1096-11862024-12-0121010750310.1016/j.phrs.2024.107503Characterization of novel nitazene recreational drugs: Insights into their risk potential from in vitro µ-opioid receptor assays and in vivo behavioral studies in miceMarthe M. Vandeputte0Grant C. Glatfelter1Donna Walther2Nathan K. Layle3Danielle M. St. Germaine4István Ujváry5Donna M. Iula6Michael H. Baumann7Christophe P. Stove8Laboratory of Toxicology, Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, BelgiumDesigner Drug Research Unit (DDRU), Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USADesigner Drug Research Unit (DDRU), Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USAForensic Chemistry Division, Cayman Chemical Company, Ann Arbor, MI 48108, USAForensic Chemistry Division, Cayman Chemical Company, Ann Arbor, MI 48108, USAiKem BT, Budapest H-1033, HungaryForensic Chemistry Division, Cayman Chemical Company, Ann Arbor, MI 48108, USADesigner Drug Research Unit (DDRU), Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USALaboratory of Toxicology, Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium; Corresponding author.2-Benzylbenzimidazole derivatives or ‘nitazenes’ are increasingly present on the recreational drug market. Here, we report the synthesis and pharmacological characterization of 15 structurally diverse nitazenes that might be predicted to emerge or grow in popularity. This work expands the existing knowledge about 2-benzylbenzimidazole structure-activity relationships (SARs), while also helping stakeholders (e.g., forensic toxicologists, clinicians, policymakers) in their risk assessment and preparedness for the potential next generation of nitazenes. In vitro µ-opioid receptor (MOR) affinity was determined via competition radioligand (3[H]DAMGO) binding assays in rat brain tissue. MOR activation (potency and efficacy) was studied by means of a cell-based β-arrestin 2 recruitment assay. For seven nitazenes, including etonitazene, opioid-like pharmacodynamic effects (antinociception, locomotor activity, body temperature changes) were evaluated after subcutaneous administration in male C57BL/6 J mice. The results showed that all nitazenes bound to MOR with nanomolar affinities, and the functional potency of several of them was comparable to or exceeded that of fentanyl. In vivo, dose-dependent effects were observed for antinociception, locomotor activity, and body temperature changes in mice. SAR insights included the high opioid-like activity of methionitazene, iso-butonitazene, sec-butonitazene, and the etonitazene analogues 1-ethyl-pyrrolidinylmethyl N-desalkyl etonitazene and ethylene etonitazene. The most potent analogue of the panel across all functional assays was α’-methyl etonitazene. Taken together, through critical pharmacological evaluation, this work provides a framework for strengthened preparedness and risk assessments of current and future nitazenes that have the potential to cause harm to users.http://www.sciencedirect.com/science/article/pii/S1043661824004481NitazeneNew synthetic opioidsIn vitro and in vivo pharmacologyStructure-activity relationships2-Benzylbenzimidazolesµ-Opioid receptor
spellingShingle Marthe M. Vandeputte
Grant C. Glatfelter
Donna Walther
Nathan K. Layle
Danielle M. St. Germaine
István Ujváry
Donna M. Iula
Michael H. Baumann
Christophe P. Stove
Characterization of novel nitazene recreational drugs: Insights into their risk potential from in vitro µ-opioid receptor assays and in vivo behavioral studies in mice
Pharmacological Research
Nitazene
New synthetic opioids
In vitro and in vivo pharmacology
Structure-activity relationships
2-Benzylbenzimidazoles
µ-Opioid receptor
title Characterization of novel nitazene recreational drugs: Insights into their risk potential from in vitro µ-opioid receptor assays and in vivo behavioral studies in mice
title_full Characterization of novel nitazene recreational drugs: Insights into their risk potential from in vitro µ-opioid receptor assays and in vivo behavioral studies in mice
title_fullStr Characterization of novel nitazene recreational drugs: Insights into their risk potential from in vitro µ-opioid receptor assays and in vivo behavioral studies in mice
title_full_unstemmed Characterization of novel nitazene recreational drugs: Insights into their risk potential from in vitro µ-opioid receptor assays and in vivo behavioral studies in mice
title_short Characterization of novel nitazene recreational drugs: Insights into their risk potential from in vitro µ-opioid receptor assays and in vivo behavioral studies in mice
title_sort characterization of novel nitazene recreational drugs insights into their risk potential from in vitro µ opioid receptor assays and in vivo behavioral studies in mice
topic Nitazene
New synthetic opioids
In vitro and in vivo pharmacology
Structure-activity relationships
2-Benzylbenzimidazoles
µ-Opioid receptor
url http://www.sciencedirect.com/science/article/pii/S1043661824004481
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