title: A simple method for the selection of a suitable emulsifier based on color difference.
abstract: The purpose of this study was to establish a simple and rapid method for selecting a nonionic surfactant to prepare an emulsion that can maintain a stable emulsification phase. As an index of the degree of emulsification, the white chromaticity of the prepared sample was measured using a color difference meter. When liquid paraffin was used as an oil, the color difference (dE(H)) was shown as a change in a V-shaped curve depending on changes in the hydrophile-lipophile balance (HLB) number of sorbitan ester, polyoxyethylene sorbitan ester, or polyethyleneglycol ester. Although there was a difference in the minimal value of dE(H) in these experiments, the dE(H) was similar to the required HLB of liquid paraffin (HLB=10). On the other hand, no relationship was found between the HLB number and color difference when polyglycerol ester was used. It seems that there was possibility of the effect by the lowering of apparent HLB with a collapse of the hydration. These results indicate that color difference could be utilized for the selection of surfactants, except for polyglycerol ester.
authors.affiliation: Faculty of Pharmaceutical Sciences, Hokuriku University, Kanazawa, Japan. k-koga@hokuriko-u.ac.jp
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Koga
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Ishitobi
authors.forename: Masaki
authors.initials: M
authors.lastname: Iwata
authors.forename: Masahiro
authors.initials: M
authors.lastname: Murakami
authors.forename: Susumu
authors.initials: S
authors.lastname: Kawashima
mesh_terms: D003124:Colorimetry / Q000379:methods; D005079:Excipients / Q000032:analysis* / Q000737:chemistry; D010860:Pigments, Biological / Q000032:analysis*
chemical_list: D005079:Excipients; D010860:Pigments, Biological