Nanomedicine for the Brain and the Eye: Disease Management in Poorly Accessible Compartments of the Body

The advent of nanodrugs allows newer strategies
to treat poorly accessible lesions, such as those
affecting the central nervous system (CNS) or the
posterior pole of the eye. These compartments
of the body are protected by biological barriers.
Their selectivity was first described around 1930, and it was finally stated that hydrophobicity
and low molecular weight are requested
features of putative drugs for the CNS.
Four decades later, techniques for assembling
lipids in liposomes were developed. Liposomes
interact with biological membranes and carry
molecules into the cytoplasm. The partially successful
attempt of exploiting liposomes as carriers
of drugs to treat brain tumors followed. It was soon clarified that, in neurology, only nanoliposomes
retained both biocompatibility and efficacy
as drug carriers and adjuvants These experimental evidences together with the bloom of nanotechnology have stimulated
researches on new nanomaterials for the diseases
of the CNS. Nanotechnology may also target the
retina, another site protected by a biological barrier
named the blood–retina barrier (BRB).