Pharmaceutical characterization of commercially available intravenous fat emulsions: estimation of average particle...

Particle profiles such as the average diameter, size distribution and dispersion, as well as the zeta potential, of commercially available intravenous fat emulsions of high-calorie nutrient fluids (6 products) and drug carriers (4 products) were examined using photon correlation spectroscopy (dynamic light scattering). Wide variations were observed in number-weighted (dn), weight-weighted (dw) and z-average diameters, and dw/dn ratios as a measure of polydispersity. Average size is not sufficient for the pharmaceutical characterization of particles and the determination of size distribution or dw/dn value is essential for more precise information. Although measuring the zeta potential of fat emulsions is of considerable value in estimating their stability on long-term storage, a medium which accurately reflects the environment of the droplets in the system of interest should be chosen when diluting the emulsion.