BBB

Neurodegenerative disorders are conditions in which cells of the brain and/or spinal cord degenerate.  The brain and spinal cord are composed of neurons with different functions such as controlling skilled movements, processing sensory information, storage of information and making decisions. Cells of the brain and spinal cord do not usually regenerate, so damage to the nervous system can be devastating. Normally, the neurodegenerative process begins long before any symptoms appear. Neurodegenerative diseases result from deterioration of neurons or their myelin sheaths which over time will lead to dysfunction and disabilities. Neuro-degenerative diseases markedly affect the lives of millions and lead to a growing public health challenge with increased costs for individuals and society. The prevention and treatment of these neurodegenerative disorders represent a critical goal of medical research today. Most of these disorders increase with age. Today, there are 25 million suffering from dementia and it is generally believed that the prevalence will be 130 million demented persons by 2050. As the human outer skin proved it to be the largest organ of sense of body, that can be potentially used for the delivery of multiple therapy for the successful management of neurobehavioral disorders. Various novel approaches can be introduced for which further study is essential .The focus on this route has not been in limelight till yet. Transdermal drug delivery is helpful for topical and local action of the drug. . For the patients who have difficulties swallowing solids or liquids, a transdermal drug delivery may offer great advantages over conventional delivery methods. Drug delivery directly to the brain interstitium has recently been markedly enhanced through the rational design of polymer-based drug delivery system. After the oral administration of drugs, the huge variations were associated in plasma levels with regular gastintestinal symptoms including nausea, vomiting, diarrhea, constipation, anorexia, abdominal pain and abdominal distention. This drug administration route could therefore allow optimal therapeutic dose, potentially further improving the effectiveness of treatment. The transdermal delivery bypasses the first past metabolism and lesser side effects. This route may be explored for the delivery of nano-sized pharmaceuticals to the CNS as an alternate route.

The worldwide CNS pathology incidence displayed that about 1.5 billion people suffer from CNS disorders. The worrying  fact that , delivering drugs to the CNS is impaired by the presence of the blood-brain barrier (BBB) that represents the main obstacle for CNS drug development, many hydrophilic drugs and neuropeptides etc are may have difficulty in crossing the blood-brain barrier. It is important to consider not only the net delivery of the agent to the CNS, but also the ability of the agent to access the relevant target site within the CNS. Many strategies have been developed to deliver the drug into brain by crossing the BBB are chemical delivery systems, magnetic drug targeting, or drug carrier systems such as antibodies, liposomes or Nanoparticles. Among those, Nanoparticles have got a great concentration as the potential targeted drug delivery systems in the brain recently. Nanoparticles (NP) are solid colloidal particles ranging in size from one to 1000nm that may be utilized as brain drug delivery carriers. Coating of Nanoparticles with drug molecules are as carriers to cross the BBB and transport the drugs to the specific sites in brain where they are needed.  NPs may provide slow drug release in blood and thereby reduces the peripheral toxicity. Key words: BBB, Drug delivery to brain, Nanotechnology, Colloidal drug carriers.