Production and Stabilization of the Therapeutic Peptide Angiotensin 1-7 for Oral Delivery

Angiotensin (Ang) 1-7 is a peptide in the renin-angiotensin system that regulates the cardiovascular and metabolic systems, making it an attractive therapeutic target for a number of disorders. However, Ang 1-7 has a short half-life in vivo, decreasing the efficacy of this therapeutic. As shown with small molecules and proteins, polymer carriers prolong the in vivo stability of therapeutics. Ang 1-7 has a net cationic charge, rendering it amenable to electrostatic encapsulation with anionic polymers. The goal of this research is to scale peptide production and study the electrostatic encapsulation of Ang 1-7 within polymers. In order to produce Ang 1-7 at appropriate scales, we improved the purification process for Ang 1-7 by modifying both analytical and preparative high-performance liquid chromatography (HPLC) elution profiles. These modifications reduced the time for a single preparative HPLC batch from 1 hour to 20 minutes, saving over 1 L of solvent. With injections of 30 mg crude Ang 1-7 per batch, we consistently recovered 65% of the peptide. For encapsulation of Ang 1-7, we also performed reversible addition-fragmentation chain-transfer (RAFT) polymerization to synthesize an anionic poly(methacrylic acid) suitable for Ang1-7 encapsulation. We confirmed the polymer structure with nuclear magnetic resonance (NMR) spectroscopy and determined the molecular weight by gel permeation chromatography (GPC). This poster describes preliminary encapsulation studies of Ang 1-7 in poly(acrylic acid) and poly(methacrylic acid) using dialysis and HPLC. These results lay the foundation for future development of an oral delivery system for Ang 1-7.