**Background**
Preterm labor, defined as the onset of labor before 37 weeks of gestation, is a significant clinical challenge that can lead to severe neonatal morbidity and mortality. Prostaglandins play a critical role in the initiation of uterine contractions and cervical ripening, with prostaglandin F 2α (PGF 2α) acting through its specific G protein-coupled receptor, the FP receptor. Antagonizing the FP receptor represents a promising therapeutic strategy to delay preterm birth and prolong gestation, thereby allowing for fetal maturation and improving neonatal outcomes. In this context, we will introduce a selective and orally active FP receptor antagonist – Ebopiprant.
**Definition**
Ebopiprant (also known as OBE022) is an oral and selective prostaglandin F 2α receptor antagonist with high binding affinity, exhibiting Ki values of 1 nM for the human FP receptor and 26 nM for the rat FP receptor.
**In Vitro and In Vivo Studies**
The Ebopiprant description highlights its potency as a competitive antagonist. In Ebopiprant in vitro assays, competitive binding analysis using 3H-PGF2α in HEK293 cells stably transfected with the FP receptor was performed. The results demonstrated that Ebopiprant (OBE022) possesses binding affinities (Ki) of 1 nM for the human FP receptor and 26 nM for the rat FP receptor. This binding is reversible and competitive, as increasing concentrations of the compound lead to successive decreases in the slope of the binding curves, indicating an increase in the equilibrium dissociation constant (KD) without reducing receptor density.
Regarding Ebopiprant In Vivo activity, the compound was evaluated in mice models of RU486-induced preterm parturition at gestational day 17 (GD17). Oral administration of Ebopiprant significantly delayed preterm birth, as evidenced by a rightward shift in the cumulative percentage of delivery curve. This effect was comparable to that of nifedipine, and both treatments showed a trend toward increasing the time to the first pup delivery, ultimately resulting in the delivery of viable pups. Furthermore, the combination of Ebopiprant and nifedipine produced a synergistic effect, causing a more pronounced delay in RU486-induced preterm birth and a larger increase in the time of first pup delivery compared to either agent alone. Based on the Ebopiprant biological activity observed, this compound serves as an effective modality for managing preterm labor. In conclusion, Ebopiprant is a potent, selective, and orally bioavailable FP receptor antagonist that holds promise for the treatment of preterm labor.
Keywords
Ebopiprant, 2005486-31-5, OBE022, OBE 022, OBE-022, Prostaglandin Receptor, Inhibitor, inhibitor, inhibit
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