[Strategies for drug delivery to the brain across the blood-brain barrier].

Designing drugs (including peptides) with greater lipophilicity are still effective strategy for the enhancement of the permeability across the blood-brain barrier (BBB), which is considered to be lipoidal membrane barrier of endothelial cells which have tight junctions without fenestrations. However, for the development of brain-specific drug delivery for neuroactive drugs, it may be greater promising strategy to utilize the specific influx transporters existing at the BBB for hexoses, amino acids, monocarboxylic acids, amines or to inhibit the functions of the efflux transporters such as P-glycoprotein which pumps out cytotoxic and/or lipophilic drugs. Attractive approach to the delivery of peptides is to design the peptide to be transported across the BBB via ologopeptide specific transporters, via insulin or transferrin receptor-mediated transcytosis, or via adsorptive-mediated transcytosis specific for positively charged peptides.