Mozavaptan (OPC31260) is a orally effective, nonpeptide vasopressin V2 receptor antagonist with an IC50 of 14 nM.
Mozavaptan causes a competitive displacement of [3H]-arginine vasopressin (AVP) binding to both V1 and V2 receptors with IC50 values of 1.2 μM and 14 nM, respectively. The Kd of [3H]-AVP is reduced significantly in both rat liver and kidney in the presence of mozavaptan (Kd=1.1 nM in liver, Kd=1.38 nM in kidney)[1].
Mozavaptan at doses of 10 to 100 μg/kg, i.v., inhibits the antidiuretic action of exogenously administered arginine vasopressin in water-loaded, alcohol-anaesthetized rats in a dose-dependent manner. Mozavaptan does not exert an antidiuretic activity suggesting that it is not a partial V2 receptor agonist. Mozavaptan dose-dependently increases urine flow and decreases urine osmolality after oral administration at doses of 1 to 30 mg/kg in normal conscious rats[1].
References:
[1]. Yamamura Y, et al. Characterization of a novel aquaretic agent, OPC-31260, as an orally effective, nonpeptide vasopressin V2 receptor antagonist. Br J Pharmacol. 1992 Apr;105(4):787-91.