ABSTRACT
The brain has a very complex structure as far as regulation of movement of such blood components and accessory nutritional counterparts are concerned. Unlike other parts of the body where there is free and easy movement of ions, electrolytes, and blood components across the various cells and tissues. The blood vessels that supply vital nutrients and oxygen to the brain are highly specialized and tightly regulate the transport process which is defined as blood-brain barrier (BBB). As brain is a central controller of all metabolic activities including voluntary and involuntary functions, it has highly specialized defense mechanism called as BBB. Neurons are structural and functional unit of brain. Further, the walls of the blood vessels are line with endothelial cells that coordinate various metabolic, barrier and transport properties. Taking into consideration the basic aspects of the structural organization and transport mechanism, this chapter provides a brief discussion of the blood brain barrier along with nature of the barrier and various strategies to overcome BBB which is essential in delivery of therapeutics to the brain in several disorders. Different In vitro culture models are discussed to assess the permeation across BBB is very crucial and significant in drug development cycle of neurotherapeutics along with in vivo pharmacokinetic and pharmacodynamic studies.
