Application of Polymeric Nanoparticles for Brain Targeting

Nanocarrier holds a widespread application in drug targeting and effective delivery to the desired site for the treatment of numerous disease conditions. Reaching the brain is truly arduous for the therapeutic moieties due to the BBB and other protective measures. A series of diverse nanocarrier systems and novel approaches have been explored to deliver bioactives to the brain effectively. Polymeric nanoparticles embrace significant capabilities for effective brain delivery by virtue of the unique characteristics of individual polymers. Chitosan, PLGA, alginate, PEG, PAMAM, etc., and their inimitable combinations or derivatives, are often used for brain targeting. The characteristic features of these polymers and nanosize facilitate the permeation of the drug-carrier system through BBB by various mechanisms like enhanced permeation, passive diffusion, active transport via receptor-mediated endocytosis, or carrier-mediated transcytosis. The surface flexibility allows the enhanced targeting via surface decoration with specialized moieties for definite functions such as PEG for stealth nature and protects from the RES system. Antibodies, high-molecular-weight proteins, and peptides and ligands against cell surface receptors like GLUT, transferrin, and lactoferrin promote carrier or receptor-mediated transport. At the same time, drug release in a controlled manner assures the therapeutic activity for prolonged duration and limits drug clearance. This chapter highlights the application of polymeric nanoparticles for brain targeting with special emphasis on various types of polymers suitable for brain delivery, including natural and synthetic polymers, methods of synthesis of polymeric nanoparticles, brain targeting approaches, and toxicological aspects.