2019 Volume 19 Issue 5 Pages 191-196
Solid-in-Oil (S/O) nanodispersion is a novel emulsion formulation, in which hydrophilic macromolecular drugs are coated with hydrophobic surfactants and dispersed in an oil phase as nano-ordered particles. In this review, history and classification of S/O nanodispersions are described. The main topic of this review is a solid-in-oil-in-water (S/O/W) emulsion that is a multiple-emulsion using a S/O nanodispersion as an oil phase of oil-in-water emulsions. The first study using the S/O/W emulsion in a drug delivery system was focused on the carrier of oral delivery. Insulin was encapsulated in the S/O/W emulsion and released in a gastric condition. In the transdermal delivery, the S/O nanodispersion is known to be effective because skin has a hydrophobic barrier and the S/O/W emulsion is also applied to the transdermal drug delivery as a water-based formulation. In addition, the S/O/W emulsion was used as an encapsulation tool for gene or proteins. The double-coating carrier was effective for the intracellular delivery of gene or proteins. These results suggested that the S/O/W multiple emulsion would be a promising carrier for the drug delivery system of biomolecules.
