7 - Brain drug delivery by adsorption-mediated transcytosis

Abstract

The unique property of the blood-brain barrier (BBB) characterized by its endothelial tight junction and a complete absence of pinocytic activity restricts >98% drugs to enter the central nervous system (CNS) from systemic circulation. Small-molecule drugs can be helped transported into brain by lipidation, chemical delivery system, and transporter-mediated way. Receptor-mediated transcytosis (RMT) and adsorptive-mediated transcytosis (AMT) can effectively increase brain drug delivery, especially macromolecular drug delivery. AMT delivers drug into brain by the electrostatic interaction between positive charge on the surface of the drug delivery system and the anion on the BBB membrane. In contrast to specific RMT, AMT is nonspecific, but high in binding capacity. In general, the efficiency of AMT to transport through the BBB is similar to that of RMT. A variety of proteins or peptides can transport through BBB into the brain via AMT, such as cationic proteins, basic polypeptides or proteins, and cell-penetrating peptides. Coupling drugs or drug delivery systems with these brain transport vectors result in adsorptive-mediated brain drug delivery system, which are mainly discussed in this chapter in detail.