In vitro uptake of polystyrene latex particles and parenteral fat emulsions by human granulocytes

Abstract

Suspensions of human granulocytes were used to study the in vitro phagocytosis of polystyrene latex particles (1030 nm) as i.v. model drug carriers and of commercial fat emulsions for parenteral nutrition (Lipofundin, Intralipid). Chemiluminescence (CL) was employed to follow the time-dependent uptake of the particle. The total uptake was quantified by the area under the curve of the CL intensity/time profiles and comparitively by a modified fluorimetric assay. The data proved that a linear relationship existed between the AUC of the CL assay and the total mass of internalized polymer. The uptake of fat emulsions could not be followed directly by CL because the CL intensity signal was too weak. Their uptake could be quantified via the impairment of the phagocytic function of granulocytes after pre-incubation with emulsion. The polystyrene particles were used as test colloid. The phagocytic function was reduced up to 50% by 10% fat emulsions.