Designer Benzodiazepines' Activity on Opioid Receptors: A Docking Study

Designer benzodiazepines: an update

INTRODUCTION

Designer benzodiazepines (DBs) are a subclass of novel psychoactive substances (NPS). DBs mimic the properties of approved and prescribed benzodiazepines.

AREA COVERED

A systematic search of literature on DB classification, structure-activity relationships, pharmacologic properties, and adverse effects.

EXPERT OPINION

The prevalence of DB use has increased substantially over the last decade. All DBs are full-agonist ligands at the gamma-aminobutyric acid type A-benzodiazepine (GABA_A-BZ) receptor system. This is not surprising, since DBs largely represent either minor structural modifications, or well-recognized active metabolites, of existing approved benzodiazepines. As such, the pharmacologic profile and associated risks and hazards of DBs are similar or identical to clinically approved and legitimately prescribed benzodiazepines, most of which have been in use for decades. Concurrent use of DBs along with other abusable or recreational drugs (alcohol, opioids, cocaine, stimulants, hallucinogens, other sedative-hypnotics) represents the principal public health risk. The increasing illicit availability and use of DBs is of concern and requires regulatory attention, but DBs do not rank highly among designer psychotropic agents in terms of health risk to humans.

In silico studies on recreational drugs: 3D quantitative structure activity relationship prediction of classified and de novo designer benzodiazepines

Currently, increasing availability and popularity of designer benzodiazepines (DBZDs) constitutes a primary threat to public health. To assess this threat, the biological activity/potency of DBZDs was investigated using in silico studies. Specific Quantitative Structure Activity Relationship (QSAR) models were developed in Forge™ for the prediction of biological activity (IC50 ) on the γ-aminobutyric acid A receptor (GABA-AR) of previously identified classified and unclassified DBDZs. A set of new potential ligands resulting from scaffold hopping studies conducted with MOE® was also evaluated. Two generated QSAR models (i.e. 3D-field QSAR and RVM) returned very good performance statistics (r2  = 0.98 [both] and q2  = 0.75 and 0.72, respectively). The DBZDs predicted to be the most active were flubrotizolam, clonazolam, pynazolam and flucotizolam, consistently with what reported in literature and/or drug discussion fora. The scaffold hopping studies strongly suggest that replacement of the pendant phenyl moiety with a five-membered ring could increase biological activity and highlight the existence of a still unexplored chemical space for DBZDs. QSAR could be of use as a preliminary risk assessment model for (newly) identified DBZDs, as well as scaffold hopping for the creation of computational libraries that could be used by regulatory bodies as support tools for scheduling procedures.