Özet:

The blood – brain barrier (BBB) is a complex multicellular structure, which composites of endothelial cells, pericytes, immune cells, astrocytes, and basement membrane, also known as the “neurovascular unit”. BBB protects the central nervous system (CNS) from the toxins and pathogens in systemic circulation. Endothelial cells are the main barrier component because of the absence of fenestrae, extremely low levels of transport vesicles, and the presence tight junctions (TJ’s), which restricts paracellular transport. Also, the presence of defense mechanisms like efflux pumps and influx pumps which are members of superfamily of membrane transporters, makes BBB impossible for penetration. These pumps regulate the entry of ions and nutrients from blood to brain. The unique nature of BBB at the same time restricts the access of a large number of therapeutic agents more than 98% of all CNS drugs into the brain. Getting drugs across the BBB is a very active field of research from past few centuries to these days. Despite of intensive research, thousands of peoples are suffering from CNS diseases, such as neurodegenerative disorders, brain tumors, HIV encephalopathy and epilepsy. Scientists from all over the world are investigating a various strategy for enhancing drug delivery through the BBB. Current methods for enhancing drug delivery classified into two groups: invasive and non-invasive methods. While invasive methods are including neurosurgical-based methods like convection-enhanced delivery, intracerebroventricular injections, intracerebral implants and also methods for disruption BBB by opening TJ`s with ultrasound and iontophoresis, non-invasive methods include using nanoparticles, Trojan horses, prodrugs technologies and inhibition of efflux transporters, Alternative technics like intranasal drug delivery are also the non-invasive methods for BBB drug delivery.

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