Nose-to-brain drug delivery by nanoparticles in the treatment of neurological disorders

Many potential drugs for the treatment of neurological diseases are unable to reach the brain in sufficient enough concentrations to be therapeutic because of the blood brain barrier. On the other hand, direct delivery of drugs to the brain provides the possibility of a greater therapeutic-toxic ratio than with systemic drug delivery. The use of intranasal delivery of therapeutic agents to the brain provides a means of bypassing the blood brain barrier in a non-invasive manner. With this respect, nanosized drug carriers were shown to enhance the delivery of drugs to CNS compared to equivalent drug solutions formulations. Neurological conditions that have been studied in animal models that could benefit from nose-to-brain delivery of nanotherapeutics include pain, epilepsy, neurodegenerative disease, and infectious diseases. The delivery of drugs to the brain via nose-to-brain route holds great promise, on the basis of preclinical and clinical data related to intranasal delivery to CNS of large molecular weight biologics administered in solution, but it is still uncertain whether drug delivered by nanoparticles are released in the nasal cavity, available for absorption, or if the drug-loaded nanoparticles are transported into CNS