Effect of the hydrophilic surfactants on the preparation and encapsulation efficiency in course and fine W/O/W type emulsions

Motohiro Shima, Yohei Kobayashi, Yukitaka Kimura, Shuji Adachi, Ryuichi Matsuno

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


Although the surfactant plays an important role in the preparation of a water-in-oil-in-water (W/O/W) emulsion, its concentration has been determined empirically. We investigated the location of a hydrophilic surfactant in a coarse W/O/W emulsion and a membrane-filtered fine emulsion. At first, appropriate concentrations of some hydrophilic surfactants to prepare a W/O/W emulsion were investigated from the viewpoints of the median diameter of the oil droplets and the encapsulation efficiency of a hydrophilic substance in the inner-water phase. The location of the surfactants and oil was examined for the W/O/W emulsions, prepared using polyglycerol monolaurate as a hydrophilic surfactant in the outer-phase solution at 1-10% (w/v) and octanoic acid triacylglycerol, which contained hexaglyceryl condensed ricinoleate as an oil-phase surfactant in the oil phase. The median diameter of the oil droplets in the W/O/W emulsion reached a minimum value at 3% (w/v) decaglycerol monolaurate (ML-750), and was constant over 4% (w/v). The excess decaglycerol monolaurate, that was not adsorbed on the oil-water interface was distributed to the outer-water and oil phases. The oil and hydrophobic surfactant were dissolved in the outer-phase solution at high concentrations of the hydrophilic surfactant. These results suggest that the hydrophilic-surfactant concentration appropriate for preparing the W/O/W emulsion would be 3% (w/v) in the outer-phase solution and that the location of the components in the W/O/W emulsion would also be useful in estimating the adequate concentration of the surfactant.

Original languageEnglish
Pages (from-to)83-90
Number of pages8
JournalColloids and Surfaces A: Physicochemical and Engineering Aspects
Issue number1-3
Publication statusPublished - May 4 2004
Externally publishedYes


  • Drug delivery system
  • Encapsulation efficiency
  • Functional food
  • Surfactant
  • W/O/W emulsion

ASJC Scopus subject areas

  • Surfaces and Interfaces
  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry


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