Passively targeted liposomal drug delivery systems have some disadvantages. Normal organ uptake of liposomes leads to accumulation of the encapsulated drug in mononuclear phagocytic system cells in the liver, spleen, and bone marrow [63] , which may present hazards to these tissues. For example, with increased circulation time of these drugs may come increased toxicity inducing such problems as handfoot syndrome, mucositis, and hematological toxicities such as neutropenia, thrombocytopenia, and leucopenia [71] [72] [73] [74] . Therefore, ongoing research aims at enhancing the tumor site-specific action of the liposomes by attaching ligands to surface molecules of tumor cells and tumor vasculature, a process called active or ligand-mediated targeting liposomes [5, 6, 13, 75] .