In Vitro Pharmacological Characterization of Buprenorphine, Samidorphan, and Combinations Being Developed as an Adjunctive Treatment of Major Depressive Disorder.

A combination of buprenorphine (BUP) and samidorphan (SAM) at a 1:1 (mg/mg) fixed-ratio dose is being investigated as an adjunctive treatment of major depressive disorder (BUP/SAM, ALKS 5461). Both [H]BUP and [H]SAM bound to the -, -, and -opioid receptors (MOR, KOR, and DOR, respectively) with K values of 3 nM or less. [H]BUP dissociated from the MOR more slowly than [H]SAM did.