Blood brain barrier

1. Blood Brain BarrierBlood Brain Barrier
Department of Veterinary Pharmacology &
Toxicology
RAJUVAS
Submitted by:
Aditya Asopa
B.V.Sc & A.H – V
Semester
Submitted to:
Dr. Mangesh Nakade
Dr. Nalini Kataria

2. Blood Brain Barrier : PhysiologyBlood Brain Barrier : Physiology
This "barrier" results from the selectivity of the tight
junctions between endothelial cells in CNS vessels that
restricts the passage of solutes.
The BBB is distinct from the quite similar blood-
cerebrospinal fluid barrier, which is a function of the
choroidal cells of the choroid plexus, and from the
blood-retinal barrier, which can be considered a part of
the whole realm of such barriers.

3. Mechanisms by which molecules move across the blood-brain barrier.

4. PathophysiologyPathophysiology
The blood-brain barrier acts very effectively to protect the brain
from many common bacterial infections.
However, the blood-brain barrier becomes more permeable during
inflammation, meaning that some antibiotics can get across. Viruses
easily bypass the blood-brain barrier by attaching themselves to
circulating immune cells.
There are also some biochemical poisons that are made up of large
molecules that are too big to pass through the blood-brain barrier.
Neurotoxins such as Botulinum in the food might affect peripheral
nerves, but the blood-brain barrier can often prevent such toxins
from reaching the central nervous system, where they could cause
serious or fatal damage.

5. Drug DevelopmentDrug Development
Overcoming the difficulty of delivering therapeutic
agents to specific regions of the brain presents a major
challenge to treatment of most brain disorders. In its
neuroprotective role, the blood-brain barrier functions
to hinder the delivery of many potentially important
diagnostic and therapeutic agents to the brain.
Therapeutic molecules and genes that might otherwise
be effective in diagnosis and therapy do not cross the
BBB in adequate amounts.

6. Mechanisms for drug targeting in the brain involve going
either "through" or "behind" the BBB. Modalities for drug
delivery through the BBB entail its disruption by osmotic
means; biochemically by the use of vasoactive substances
such as bradykinin; or even by localized exposure to high-
intensity focused ultrasound (HIFU).
Other methods used to get through the BBB may entail the
use of endogenous transport systems, including carrier-
mediated transporters such as glucose and amino acid
carriers; receptor-mediated transcytosis for insulin or
transferrin; and the blocking of active efflux transporters
such as p-glycoprotein.
Methods for drug delivery behind the BBB include
intracerebral implantation (such as with needles) and
convection-enhanced distribution. Mannitol can be used in
bypassing the BBB.

7. Outline of a program for developing BBB drug targeting strategies
derived from either chemistry-based or biology-based disciplines.

8. Nanotechnology in Drug TargetingNanotechnology in Drug Targeting
Nanotechnology may also help in the transfer of drugs
across the BBB.
Recently, researchers have been trying to build
liposomes loaded with nanoparticles to gain access
through the BBB.
A significant amount of research in this area has been
spent exploring methods of nanoparticle-mediated
delivery of antineoplastic drugs to tumors in the central
nervous system.

9. ConclusionConclusion
The incorporation of BBB drug delivery
strategies within the global CNS drug-
development effort is virtually
nonexistent. Considering the rate-limiting
role played by the BBB in the
development of nearly all new drugs for
the brain, it is difficult to understand why
the BBB has been so consistently
underdeveloped in both academic and
industry laboratories.

10. Given the chronic underdevelopment of BBB
transport biology within academic
neurosciences, there is no worldwide
infrastructure or critical mass of scientists
trained in BBB transport biology. This lack of
global BBB infrastructure is the single most
important factor that will limit the future of
brain drug development.