ABSTRACT
This chapter discusses adverse affects associated with in vivo administration of lipids, as liposomes or lipid emulsions. It provides an overview of the biodistribution and pharmacokinetics of phospholipids is necessary to any understanding of adverse effects associated with in vivo administration of phospholipids. The principal site of clearance of particulate matter, including phospholipid vesicles, from the circulation in vivo is the mononuclear phagocyte system (MPS), also referred to by the older term reticuloendothelial system. The MPS is the principal in vivo site of uptake of foreign particulate matter and therefore is the tissue most likely to sustain damage following administration of phospholipid vesicles in vivo. Stealth liposomes are liposomes in which the lipid composition and liposome surface properties have been altered to result in significant reductions in their recognition and uptake by the cells of the MP system. Also important in avoiding MPS uptake is the absence of negative charges directly exposed at the liposome surface.
