Particle size and zeta potential of the emulsion droplets are important physical characteristics that influence emulsion stability.

Emulsions are two phase dispersion of liquids that are normally not miscible. The most common examples are oil in water and water in oil. The particle size and zeta potential of the emulsion droplets are important physical characteristics that influence emulsion stability.

Droplet size can be measured on either the Nicomp® DLS system or the AccuSizer® SPOS system. The Nicomp system can also measure the zeta potential during the formulation, which optimizes the surface chemistry and dispersion stability.

The AccuSizer system is extensively used to measure emulsion droplet size in lipid injectable emulsions (total parenteral nutrition, or TPN) following the USP <729> Method II testing procedure, and soft drink flavor emulsions.