Coating of liposomes with polyethylene glycol (PEG) has proven to prolong the circulation time of liposomes in the blood stream. PEG prevents the binding of opsonins and subsequent uptake of the liposomes by mononuclear phagocytic system (MPS). The reduction in clearance of PEGylated liposomes from the circulation improve the bioavailability of the liposomes in the blood and increase the chance of ...