Stabilization of Glucagon by Trehalose Diblock Copolymer Vesicles for Hypoglycemic Counterregulation

Abstract Hypoglycemia remains a major challenge in type-1 diabetes, requiring rapid glucagon delivery; however, current formulations are limited by poor aqueous stability and reconstitution constraints. A stable, injectable glucagon formulation in an aqueous solution could transform treatment, enabling mini-dosing for mild-to-moderate hypoglycemia or continuous infusion in closed-loop systems. Here, we introduce supramolecular poly(trehalose) diblock copolymer nanoparticles via polymerization-induced self-assembly (PISA) to generate distinct nanoparticle morphologies. A cysteine-modified glucagon analogue (Q24C) was conjugated to poly(trehalose methacrylate) coronas via pyridyl disulfide exchange. Glucagon stabilized by vesicles demonstrated enhanced resistance to degradation and fibrillation in aqueous media, maintaining stability for 30 days at 23−24 °C and upon solution heating. Glucagon−vesicle conjugates effectively reversed insulin-induced hypoglycemia in male mice, maintaining glucose-counterregulatory activity after 30 days of storage at 23−24 °C. These findings highlight that polymer-stabilized glucagon nanoformulations overcome longstanding stability barriers while preserving biological activity, offering a robust platform for treating insulin-induced hypoglycemia in type-1 diabetes.