Ebopiprant (OBE022) is an orally available, selective and potent prostaglandin F2α (PGF2α) receptor antagonist that interferes with the binding of PGF0126α to the FPR and can be used in the study of obesity.

FPR:26 nM (Ki, Rat), FPR:1 nM (Ki, Human)

Ebopiprant (OBE022) and OBE002 undergo FP binding affinity assays via competitive binding with 3H-PGF2α, utilizing HEK293 cells stably transfected with the FP receptor. The binding affinities (Ki) of Ebopiprant (OBE022) for human and rat FP receptors are 1 nM and 26 nM, respectively, while for OBE002, they are 6 nM for human FP and 313 nM for rat FP. The binding of both compounds is reversible and competitive, with increasing concentrations leading to decreased slopes of the binding curves, indicating an increase in the equilibrium dissociation constant (KD) without reducing receptor density[1].

In the time-course study of the cumulative percentage of delivered mice after RU486-induced preterm parturition at GD17, oral treatment with Ebopiprant (OBE022)or nifedipine, as well as vehicle treatment, was assessed. Both Ebopiprant (OBE022) and nifedipine treatments resulted in a delay in preterm birth caused by RU486 administration, evidenced by a rightward shift in the percentage of delivery curve. Notably, both compounds showed a trend towards an increased time to the first pup delivery. This prolongation of gestation led to the delivery of viable pups.Furthermore, the combination of Ebopiprant (OBE022) and nifedipine exhibited a synergistic effect on delaying RU486-induced preterm birth, as indicated by a more pronounced rightward shift in the percentage of delivery curve compared to Ebopiprant (OBE022) or nifedipine alone. Additionally, a larger increase in the time of the first pup delivery was observed with the combination treatment[1].