Development of a Novel Spontaneous Emulsification Method for Peptide Delivery Using Porous Silica Particles.

A new emulsification technique using porous silica particles was studied as a facile and instantaneous formation method for thermodynamically unstable emulsions. In this study, oil encapsulated in silica particles was released instantly upon the addition of a phosphate buffer, forming an oil-in-water (O/W) emulsion. Emulsion formation was inhibited or promoted using lipophilic or hydrophilic surfactant additives, respectively. We concluded that this phenomenon is affected by the wettability of the soybean oil on the silica surface, which is controlled by the surfactant. We prepared submicron size emulsions in a simple method involving the addition of the silica particles to an aqueous solution. This spontaneous emulsification technique could be applied to the formation of solid-in-oil-in-water (S/O/W) emulsions for oral delivery of hydrophilic peptide medicine.