Development of Lipid-β-Sitosterol Small Unilamelar Liposomes as Vehicles for Gentisic Acid

Abstract

Liposomes, as biodegradable, non-toxic and non-immunogenic drug delivery systems, can provide controlled release of active molecules and their protection from degradation. Therefore, the aim of the present study was encapsulation of gentisic acid (antioxidant polyphenols acid) into liposomes containing phospholipids (Lipoid) and various amounts of β-sitosterol. Liposomal bilayer containing β-sitosterol was more fluid and flexible, in comparison to pure Lipoid liposomes. Gentisic acid has caused the rearranging of the acid chains of phospholipids bilayer in the 1-(4-Trimethylammoniumphenyl)-6-Phenyl-1,3,5-Hexatriene p-Toluenesulfonate (TMADPH) environment. Liposomal vesicles containing Lipoid and β-sitosterol have smaller diameter compared to pure Lipoid, whereas there is no statistically significant difference in polydispersity index (PDI). Additionally, higher concentration of β-sitosterol has induced the increase of absolute zeta potential values and consequently higher stability of liposomal suspension. The addition of various amounts of gentisic acid did not influence the changes of particle size and PDI values, while in Lipoid liposomes gentisic acid has induced significant and gradual increase of zeta potential. Lipid peroxidation was higher in Lipoid-β-sitosterol system, particularly in Lipoid 50%-β-sitosterol 50% sample, whereas gentisic acid has reduced rate of membrane lipid peroxidation. In comparison to pure Lipoid, Lipoid-β-sitosterol system has shown better membrane permeability, smaller particle size, higher zeta potential and stability, which made Lipoid-β-sitosterol liposomes suitable delivery system for gentisic acid.