An attempt at preparing water-in-oil-in-water multiple-phase emulsions

Abstract

It has been found that W/O/W-type multiple-phase emulsions can be prepared by a two-step procedure of emulsification using a variety of nonionic emulsifying agents. The first step in emulsification, providing the W O emulsion, was made with an organophilic emulsifying agent such as Span 80, and the second step, providing the W/O/W emulsion, was then carried out by mixing the W O emulsion with an aqueous solution of a polyoxyethylene-type hydrophilic emulsifying agent. Yield of the W/O/W emulsion was measured by the amount of marker (glucose), which migrated from the dispersed globules to the continuous phase, using dialysis for separating the migrated glucose from the newly prepared W/O/W emulsion, and using Nelson-Somogyi's technique for analyzing the amount of the glucose. The results of the yield measurement for a series of the samples indicate that the significant factor affecting the W/O/W emulsion formation is the ratio of the organophilic emulsifying agent in the oil phase to the hydrophilic emulsifying agent in the aqueous continuous phase. The correlation between the yield of the W/O/W emulsion and the ratio of emulsifying agents used for the two-step in emulsification shows that when one desires a yield of the W/O/W emulsion higher than 90%, the organophilic emulsifying agent needed is 10 times or more the amount of the hydrophilic emulsifying agent.