Mozavaptan (OPC-31260) is a competitive antagonist of vasopressin receptors, targeting both V1 and V2 receptors, with IC50 values of 1.2 μM and 14 nM, respectively.

V1 receptor:1.2 μM, V2 receptor:14 nM

Mozavaptan (OPC-31260) is a nonpeptide, orally effective competitive inhibitor of AVP with a V2:V1 receptor selectivity ratio of 25:1 indicating relative V2 receptor selectivity. [1] Mozavaptan (OPC-31260) inhibits AVP binding to V1 and V2 receptors in a competitive manner. [2]

Mozavaptan (OPC-31260) inhibits the antidiuretic action of exogenously administered AVP in water-loaded, alcohol-anaesthetized rats in a dose-dependent manner. OPC-31260 dose-dependently increases urine flow and decreased urine osmolality after oral administration at doses of 1 to 30 mg/kg in normal conscious rats. [2]

To determine binding kinetic constants, liver or kidney plasma membranes are incubated with increasing concentrations of [3H]-AVP with or without excess (1 μM) unlabelled AVP to obtain a saturation curve. To investigate whether mozavaptan interacts competitively or noncompetitively, the saturation binding of [3H]-AVP is examined in the absence and presence of mozavaptan at concentrations of 0.3 μM and 1 μM in liver membranes and 3 nM, and 10 nM in kidney membranes. Data on the saturation curve are plotted according to the method of Scatchard and fitted by a regression analysis[1].