Two-time window and multiangle photon correlation spectroscopy size and zeta potential analysis - Highly sensitive rapid assay for dispersion stability

Polysaccharide-stabilized iron oxide particles are highly potent contrast a gents in magnetic resonance imaging, After intravenous injection, the size of these small or ultrasmall particles strongly influences their distributi on in the body. Knowledge about the uniformity of particle size distributio n within this particle size range is not accessible by laser diffraction (l ower edge of detection range), and photon correlation spectroscopy (PCS) da ta only yield insufficient information, the so-called polydispersity index. A combination of two-time window and multiangle analysis makes detailed ch aracterization of particle size distribution and particle aggregation feasi ble, which was shown using five different iron oxide dispersions. Additiona l particle charge characterization yielded conclusions about the type of st abilization present in the dispersion - electrostatic or steric stabilizati on. Thus, this thorough particle size and charge analysis is a tool for qui ck detection of broad particle distributions or aggregates. (C) 2000 Wiley- Liss, Inc. and the American Pharmaceutical Association.