Comparative Estimation of the Liposomal Content of Phosphatidylcholine : Triolein Emulsions Using Fluorescence Quenching and ¹H-NMR Techniques

Abstract

The proportions of phosphatidylcholine (PC) molecules forming liposomes and the monolayer of emulsion particles in sonicated dimyristoyl or egg yolk PC/triolein dispersions (emulsions) were estimated by fluorescence quenching, using phosphatidylethanolamine with its hydrophilic group labelled with a fluorescent dansyl group, and by the ¹H-NMR signal shift of the choline-methyl proton of PC using a paramagnetic shift agent. From a comparison of the values estimated by the fluorescence and ¹H-NMR methods, it was concluded that the fluorescence method slightly underestimates the proportion of PC molecules in liposomes but can be effectively used to estimate the liposomal content of lipid dispersions due to the sensitivity and the relative simplicity of the basic methodology and instrumentation.