Monocytes are leading component of the mononuclear phagocytic system that play a key role in
phagocytosis and removal of several kinds of microbes from the body. Monocytes are bone marrow precursor
cells that stay in the blood for a few days and migrate towards tissues where they differentiate into macrophages.
Monocytes can be used as a carrier for delivery of active agents into tissues, where other carriers have no significant
access. Targeting monocytes is possible both through passive and active targeting, the former one is simply
achieved by enhanced permeation and retention effect while the later one by attachment of ligands on the surface
of the lipid-based particulate system. Monocytes have many receptors e.g., mannose, scavenger, integrins, cluster
of differentiation 14 (CD14) and cluster of differentiation 36 (CD36). The ligands used against these receptors are
peptides, lectins, antibodies, glycolipids, and glycoproteins. This review encloses extensive introduction of monocytes
as a suitable carrier system for drug delivery, the design of lipid-based carrier system, possible ways for
delivery of therapeutics to monocytes, and the role of monocytes in the treatment of life compromising diseases
such as cancer, inflammation, stroke, etc.