Abstract
The electrical properties (ζ-potential) of the interface have been studied in order to learn the biological significance of the surface activity in pharmacological actions. The rabbit red cells were used to measure the ζ-potential. This is known from the following formula : V ζ·D·I/η·K (V : electrophoretic velocity, D : dielectric constant, I : electric current, η : viscosity, K : conductivity). The results : Tween 80, G 2162, Lazal, Aerosol IB, sod. cholatate and saponin decreased the electrophoretic velocity. On the contrary, Span 20 and sod. lauryl sulf. increased it. The changes in velocity can be regarded as the changes in ζ-potential of red cell surface, because it was ascertained by other experiments that the viscosity, conductivity and dielectric constant were not altered by surfnce active agents in lower concentrations used in the experiments on electrophoresis.
