Chitosan-modified liposomes for improved oral delivery of dihydromyricetin: synergistic stabilization, pH-responsive release, and markedly enhanced bioaccessibility.

In this study, chitosan-modified dihydromyricetin liposomes (CHI-DMY-Lips) were developed via electrostatic adsorption to overcome the low bioavailability of dihydromyricetin (DMY). Employing conventional DMY liposomes (DMY-Lips) as controls, a comprehensive assessment was conducted on the physicochemical properties, activity preservation, in vitro release kinetics, as well as the structural stability and bioaccessibility during simulated gastrointestinal (GI) digestion of the delivery system. CHI-DMY-Lips exhibited a positive surface charge with larger size, more uniform distribution, and higher encapsulation efficiency (54.00% compared to 41.01% in DMY-Lips). The encapsulation by liposomes preserved the antioxidant activity of DMY, whereas CHI further augmented its activity through synergistic effects. CHI-DMY-Lips presented enhanced structural and electrostatic stability during storage and superior in vitro sustained-release performance (especially at pH 7.4). Besides, CHI-DMY-Lips retained structural integrity throughout GI digestion and preserved its effective concentration and activity, resulting in a bioaccessibility approximately threefold that of free DMY (25.97% vs. 9.73%).