Nanomolar-affinity, non-peptide oxytocin receptor antagonists

Area of Science:

• Medicinal Chemistry
• Pharmacology
• Endocrinology

Background:

• Oxytocin (OT) is a peptide hormone crucial for social bonding and reproduction.
• Developing non-peptide antagonists for OT receptors presents a significant therapeutic challenge.
• Existing OT antagonists often lack sufficient potency or favorable pharmacokinetic properties.

Purpose of the Study:

• To design and synthesize novel non-peptide oxytocin receptor antagonists.
• To enhance the affinity and oral bioavailability of OT antagonists.
• To evaluate the efficacy of new antagonists in inhibiting oxytocin-mediated effects, particularly uterine contractions.

Main Methods:

• Structure-activity relationship (SAR) studies based on the lead compound L-366,509.
• Incorporation of novel amido- and amidoalkylcamphor modifications.
• In vitro receptor binding assays to determine OT receptor affinities.
• In vivo pharmacokinetic studies to assess oral bioavailability and duration.
• In vitro and in vivo models to evaluate inhibition of OT-stimulated uterine contractions.

Main Results:

• Novel non-peptide compounds with nanomolar oxytocin receptor affinities were synthesized.
• Affinity enhancements of 2-3 orders of magnitude were achieved compared to the lead structure.
• The compound L-367,773 demonstrated oral bioavailability and prolonged duration of action in vivo.
• L-367,773 effectively inhibited oxytocin-stimulated uterine contractions in multiple experimental models.

Conclusions:

• Novel amido- and amidoalkylcamphor derivatives represent a promising class of non-peptide oxytocin antagonists.
• L-367,773 is a potent, orally bioavailable oxytocin antagonist with demonstrated efficacy in inhibiting uterine contractions.
• These findings support the potential therapeutic application of these novel compounds in conditions involving oxytocin modulation.