Hydrothermal Preparation of Faceted Vesicles Made of Span 40 and Tween 40 and Their Characterization

• Published in: Applied sciences Vol. 13; no. 12; p. 6893
• Main Authors: Shimanouchi, Toshinori, Komori, Yui, Toramoto, Kazuki, Hayashi, Keita, Yasuhara, Kazuma, Jung, Ho-Sup, Kimura, Yukitaka
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-06-2023
• Subjects: Calcein; Drug carriers; Drug delivery; Drug delivery systems; Drugs; emulsification; Fatty acids; Fluidity; Hydration; Lipids; Membrane fluidity; Membranes; Physical properties; Polyoxyethylene sorbitan monolaurate; solvent diffusion; Solvents; Sorbitan; subcritical water; Surface active agents; Surfactants; Thin films; Vehicles; Vesicles; Zeta potential
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app13126893

The Span 40 (sorbitan monooleate)/Tween 40 (polyoxyethylene sorbitan monolaurate) system gives faceted vesicles with angular surfaces, rather than spherical vesicles. Herein, a continuous and facile preparation method, based on the subcritical water-assisted emulsification and solvent diffusion, was presented to yield faceted vesicles with two major and minor axes (Type A) and vesicles closer to a polyhedron (Type B). Type A, rather than Type B, vesicles were likely to be formed. From the measurements concerning ζ-potential, membrane fluidity, and the polarization environment of the membranes, faceted vesicles could be obtained at 0.25 wt% of the surfactant concentration. The phase-separated behavior of Span 40 and Tween 40 within vesicle membranes could explain the structural feature of faceted vesicles and calcein leakage behavior. The significant advantage is that Type A vesicles would be utilized as alternative drug carriers for others with low encapsulation efficiency, although the present technical limitations cause difficulty in the selective formation of Type A and B vesicles and the selection of adequate solvent to accelerate the solvent diffusion step.