Axelopran sulfate is an opioid receptor antagonist with pKi values of 9.8, 8.8 and 9.9 for human recombinant μ and δ receptors and guinea pig κ receptor, respectively.
References
[1] Tsuruda PR, et al., The in vitro pharmacological profile of TD-1211, a neutral opioid receptor antagonist. Naunyn Schmiedebergs Arch Pharmacol. 2013 Jun;386(6):479-91. DOI:10.1007/s00210-013-0850-7
