Effect of gentisic acid on the structural-functional properties of liposomes incorporating β-sitosterol

[Display omitted] •The obtained multilamellar vesicles were between 1350 and 1900 nm.•Gentisic acid was effectively encapsulated when nGA/nlip was higher than 0.01.•Suppression of lipid peroxidation was directly related to concentration of GA.•Diffusion resistance of GA increased for 50% in samples with 50 mol % β-sitosterol.•GA release in vitro was affected by pH of SGF and the presence of cholates in SIF. Multifunctional liposomes incorporating β-sitosterol were developed for delivery of gentisic acid (GA). The interactions of both compounds with phospholipid bilayer were interpreted viaeffects of different β-sitosterol content (0, 20 and 50 mol %) and different gentisic acid to lipid ratio (nGA/nlip from 10-5 to 1) on membrane fluidity and thermotropic properties. Multilamellar vesicles of phosphatidylcholines (with size range between 1350 and 1900 nm) effectively encapsulated GA (54%) when nGA/nlip was higher than 0.01. Suppression of lipid peroxidation was directly related to concentration of GA. The resistance to diffusion of gentisic acid from liposomes increased for ˜50% in samples incorporating 50 mol % β-sitosterol compared to sterol-free liposomes. Finally, simulated in vitro gastrointestinal conditions showed that the release was mainly affected by low pH of simulated gastric fluid and the presence of cholates in simulated intestinal fluid, rather than by enzymes activity.