Abstract:
Brain related disorders such as Alzheimer’s, Parkinson’s, brain tumors etc are emerging as serious future health threat.1 At present, according to world health organization (WHO) one in four people are affected by neurological disorders in the world. Further, depressive disorders are the fourth leading cause of the global disease and are expected to rank second by the year 2020.2 Consequently, there have been tremendous research efforts worldwide for developing drugs for the treatment of brain related disorders.3 However, the available drugs are only a few in number.4 A review of the comprehensive medicinal chemistry database shows that, out of 7000 potential small-molecule drugs, less than 5% were successful in treating brain related disorders.5 The situation of large-molecule drugs is even worst. This is because more than 95% of the small molecule drugs and almost 100% of the large molecule drugs could not cross the blood-brain barrier (BBB), which separates the brain tissues from the blood flow.6
