An Overview of Various Approaches for Brain Targeted Drug Delivery System

The blood-brain barrier (BBB) protects the central nervous system, one of the body’s most fragile microenvironments, by controlling its homeostasis. The BBB is a very complex system that strictly restricts the transport of ions from the blood to the brain of a confined amount of tiny molecules and a much lower number of large molecules, defending the brain from diseases and injuries. However, the BBB severely inhibits drug transport to the brain, hindering the treatment of various neurological problems. As a result, numerous techniques are under development to improve drug delivery across the BBB. This review summarizes the anatomical and physiological characteristics of the barriers and the current drug delivery strategies for the brain. Although these methods provide many fascinating possibilities for targeting and brain delivery, only a few have progressed to the point where they can be used safely and effectively in humans. In addition, concerted efforts using a variety of other methodologies will enable the translation of preclinical findings into tangible clinical applications in the targeted delivery of drugs.