CHEMBL5733133

Binding Competition Assay: The ability of compounds of the invention to inhibit the binding of the NK-3 receptor selective antagonist 3H-SB222200 was assessed by an in vitro radioligand binding assay. Membranes were prepared from Chinese hamster ovary recombinant cells stably expressing the human NK-3 receptor. The membranes were incubated with 5 nM 3H-SB222200 (ARC) in a HEPES 25 mM/NaCl 0.1M/CaCl2 1 mM/MgCl2 5 mM/BSA 0.5%/Saponin 10 μg/ml buffer at pH 7.4 and various concentrations of compounds of the invention. The amount of 3H-SB222200 bound to the receptor was determined after filtration by the quantification of membrane associated radioactivity using the TopCount-NXT reader (Packard). Competition curves were obtained for compounds of the invention and the concentration that displaced 50% of bound radioligand (IC50) were determined by linear regression analysis and then the apparent inhibition constant (Ki) values were calculated by the following equation: Ki=IC50/(1+[L]/Kd) where [L] is the concentration of free radioligand and Kd is its dissociation constant at the receptor, derived from saturation binding experiments (Cheng and Prusoff, 1973)