STRATEGIES FOR DELIVERY OF PEPTIDE DRUGS TO THE CENTRAL-NERVOUS-SYSTEM - EXPLOITING MOLECULAR-STRUCTURE

Peptides do not enter the central nervous system freely because of the existence of the blood-brain barrier. However, numerous peptides have been shown to alter central nervous activity and the extraction of a number of peptides at the blood-brain interface has been quantified and described. Some peptides appear to diffuse passively into the central nervous system whilst others exhibit extremely specific carrier-mediated uptake. Many peptides and their analogues are extremely potent substances and thus only relatively minute amounts of active material may actually need to reach the site of action in order to produce a central nervous effect. In targeting peptides to the central nervous system attention must be focused both on increasing bioavailability by extending the half-life in the body and enhancing brain uptake.