Polylysine‐Based Complex Coacervates as <scp>pH</scp>‐Responsive Carriers for Doxorubicin Hydrochloride

ABSTRACT Complex coacervation is a versatile and efficient technique for encapsulating bioactive molecules, with broad applications in the food and pharmaceutical industries. The process relies on the cooperative electrostatic interaction between oppositely charged polyelectrolytes in aqueous media. In this study, we present a simple and effective strategy for preparing polyelectrolyte complexes (PECs) using polylysines as cationic polypeptides and pectin as the anionic counterpart. Specifically, we utilized biosynthetically produced epsilon‐polylysine (εPL), an emerging and accessible polypeptide, to develop pH‐responsive nanocarriers for the encapsulation and controlled release of doxorubicin hydrochloride. Our coacervation‐based approach achieved high encapsulation efficiencies, with successful pH‐triggered drug release via complex dissociation. This simple εPL‐based PEC formulation, using accessible biopolymers, shows promise for drug delivery applications.