ABSTRACT
Many neurotherapeutics are unsuccessful in treating CNS disorders because they cannot be effectively drug delivered. Drug delivery to the brain is a challenge even though there is relatively high blood flow. There are two physiological barriers likes blood-brain barrier and blood-cerebrospinal fluid barrier which separates the brain from its blood supply controlling the transport of compounds. Many of the brain or CNS associated diseases remain untreated by effective therapies. This is not because there is a lack of candidate drugs but due to the inability of many therapeutic molecules to cross the BBB, the BCSFB or other specialized CNS barriers to reach the specific areas of brain. Hence there is a need in the modern approaches and present insights into using ligand conjugation and nanotechnology to target the BBB via different transport pathways and mechanisms. The field of novel drug delivery system has fully emerged and came into existence as an ideal approach of drug targeting and delivery to brain. The new approaches of drug delivery to brain help in successful transporting drugs across the BBB.