Studies on the interaction of charge-reversed emulsions with the reticuloendothelial system

Abstract

The effect of charge reversal on the uptake of fat emulsions by the reticuloendothelial (RE) system has been assessed by in vitro and in vivo methods. Emulsions stabilized by egg lecithin were charge reversed from negative to positive by added calcium ions that are adsorbed at the emulsion surface. The interaction of positively charged emulsion droplets with rat Kupffer cells was not significantly different to that found with negatively charged emulsion droplets. In all cases the measured uptake was low. Blockade of the reticuloendothelial system by infused fat emulsion was evaluated in vivo using a rabbit model. RE function was quantified by means of a probe in the form of radiolabelled albumin microspheres together with gamma scintigraphy. The kinetics of uptake of the probe into the liver/spleen regions and organ analysis showed that there were no differences between conventional and charge reversed systems. The extent of RE blockade was small in all cases.