An Overview of Drug Delivery to the CNS

Limitation of drug delivery to the central nervous system (CNS) is a major problem in development of successful treatment of CNS disorders. Concepts of blood–brain barrier (BBB), its role in transport of various substances from the blood to the brain, as well as strategies to deliver drugs across the BBB have evolved over the past century. This chapter is an overview of the challenges and various approaches to drug delivery in CNS disorders as an introduction to other chapters, which deal with laboratory and clinical methods of CNS drug delivery. A classification of current strategies for drug delivery across the BBB is presented. These include novel formulations of drugs such as nanoparticles and strategies to cross the BBB. Drugs can be introduced directly into the CNS and various devices are used for this purpose. Drugs can be administered systemically by various routes for targeted delivery to the site of action. Various methods of cell and gene therapies are used for drug delivery to the CNS. Finally, methods of delivery are classified according to various neurological disorders.