Self-assembled vesicles formed by C18 unsaturated fatty acids and sodium dodecyl sulfate as a drug delivery system

Fatty acids, as anionic surfactants, can form different self-assembled structures in alkaline solutions. It has been reported that unsaturated fatty acids (UFAs) are more likely to form vesicles in this condition. Generally, fatty acid vesicles are formed near their respective pKa (8–9), which is far from the neutral range to which the life system fits. Furthermore, vesicles formed by UFAs are extremely sensitive to pH, which limit their application. To solve this problem, we added sodium dodecyl sulfate (SDS), an anionic surfactant, to the vesicles formed by C18 UFAs to adjust the ionic effect in aqueous solution. Thereby, the formed pH windows of vesicles are migrated and expanded, which can be close to the pH range of physiological environment. Meanwhile, the vesicles formed by SDS-UFAs were determined by cryogenic transmission electron microscopy (cryo-TEM) and particle size analyzer to obtain nanocarriers with a particle size of 200–300 nm. Afterwards, the hemolysis, cytotoxicity, sustained release behavior and cellular uptake of drug-loaded nanocarriers were evaluated in vitro. This result can provide theoretical guidance for the application of drug-loaded vesicles in drug delivery system.