Potent, non-peptide and orally active oxytocin receptor antagonist (IC50 = 8.9 nM) that displays > 40-fold selectivity over vasopressin V1a and V2 receptors (IC50 values are 370 and 570 nM respectively). Antagonizes oxytocin-induced uterine contractions in vitro and in vivo. Purity 97%. MW (observed): 591.23