Discovery of 6α-Thiazolylcarboxamidonaltrexamine Derivative (NTZ) as a Potent and Central Nervous System Penetrant Opioid Receptor Modulator with Drug-like Properties for Potential Treatment of Opioid Use Disorder

The development of highly potent and selective μ opioid receptor (MOR) modulators with favorable drug-like properties has always been a focus in the opioid domain. Our previous efforts led to the discovery of a lead compound designated as NAT, a potent centrally acting MOR modulator. However, the fact that NAT precipitated considerable withdrawal effects at higher doses largely impaired its further development. In the light of the concept of activity cliff and CNS multiparameter optimization algorithm, a nitrogen atom was incorporated into the thiophene ring of NAT, aiming to preserve desirable pharmacological activities and CNS permeability while alleviating withdrawal symptoms. Among all 16 new analogs, compound 6 (NTZ) exhibited improved opioid receptor selectivity, enhanced in vivo antagonistic effect, and overall fewer withdrawal symptoms compared to NAT. Further assessment of several key drug-like properties suggested a favorable ADMET profile of NTZ. Taken together, NTZ shows promise as a potential lead to treat opioid use disorder.