Design and Development of a Cyclic Decapeptide Scaffold with Suitable Properties for Bioavailability and Oral...

Area of Science:

• Medicinal Chemistry
• Drug Discovery
• Peptide Therapeutics

Background:

• Macrocyclic peptides show therapeutic promise but face challenges in oral bioavailability and cell permeability.
• Current limitations include poor proteolytic stability, high clearance, and restricted use to extracellular targets and intravenous administration.

Purpose of the Study:

• To develop a general cyclic decapeptide scaffold with enhanced cell permeability and oral exposure.
• To overcome the limitations of macrocyclic peptides in drug delivery and systemic exposure.

Main Methods:

• Designed a rigid hairpin scaffold to reduce polarity and improve membrane penetration.
• Incorporated d-proline at the i+1 turn position to stabilize the β-hairpin conformation.
• Utilized NMR spectroscopy for conformational and dynamic analysis.

Main Results:

• Achieved unprecedented high oral bioavailability and exposure with novel cyclopeptide decamers.
• Demonstrated the importance of scaffold rigidity and d-proline for improved permeability and clearance.
• NMR data confirmed scaffold rigidity, transannular hydrogen bonds, and entropy-driven membrane permeation.

Conclusions:

• The developed cyclic decapeptide scaffold offers a promising strategy for enhancing oral delivery of peptide therapeutics.
• Rigidity and specific amino acid substitutions are key for improving peptide pharmacokinetic properties.
• The findings provide insights into the entropic contributions to membrane permeation for peptide drugs.