Novel delivery system: a liquid crystal emulsion containing HSO crystals

Abstract

Oil-in-water (O/W) emulsions with lamellar liquid crystal interfaces are promising drug-delivery systems for topical formulations. In this study, a novel delivery system—an O/W liquid crystal emulsion system containing an oil crystal network—was constructed by introducing a fully hydrogenated soybean oil (HSO) to a liquid crystal emulsion, and then the properties of the system were studied in detail. The results showed that with the introduction of the HSO, the Maltese cross patterns of the liquid crystal interface became brighter and subtle crystals of HSO gradually appeared in the inner of the liquid crystal texture. The aliphatic acid and triacylglycerols (TAGs) in HSO participated in the orderly arrangement of the lamellar interfacial phase, which not only benefited the formation of liquid crystals and recovery of the interfacial dynamic equilibrium at higher temperature but also endowed the system with a stronger interfacial film and better thermal stability. The aliphatic acid and TAGs recrystallized inside the emulsion droplets, forming a crystal network inside the droplets. The combination of HSO crystals and liquid crystals increased the characteristic temperature (T_c) of the liquid crystals and decreased the HSO melting point, which benefited the display performance of the liquid crystal emulsion and the effective application of the HSO. At the same time, the formation of both a strengthened interfacial film of liquid crystal and three-dimensional HSO crystal network inside the droplets made the emulsion system show better storage stability, mechanical strength, and deformation resistance. Furthermore, the unique structure of the liquid crystal emulsion containing HSO crystals endowed the system with an excellent sustainable release property and potential application prospects in medicine, personal care, and other fields. The present study not only provides an effective delivery system but also expands the application potential of HSO and liquid crystal emulsion systems in practice.