Background: Drug targeting to brain has always been problematic due to Blood-Brain Barrier
(BBB), which, does not allow most of the drugs to pass through it as they are hydrophilic and
macromolecular drugs. So, in order to bypass the BBB, alternative modes of administration were
searched and nasal to brain delivery route was tried by many workers. Such studies yielded patented
nano-formulations with the ability to cross blood brain barrier.
Methods: Nanoparticles being smaller in size and large surface area help in increasing the rate of drug
permeation to the brain. In this review work, emphasis has been laid on discussion on various works
done in the field of nasal delivery of drugs to brain over the last decade.
Results: The works that are discussed in this paper show better drug targeting of brain when given through nasal route as
nanoparticles. Experiments performed in animal models have clearly exhibited that nano-sized formulations are able to facilitate
the delivery of drugs to brain through nose in comparison to tantamount drug solutions.
Conclusion: However, it is not yet confirmed whether the drug is freed from the formulation in the nasal cavity and then
absorbed or the nanoparticles themselves are absorbed and then the drug is released in the CNS. Furthermore, the toxicity
studies were not carried out extensively in suitably designed model, which should be considered before going for further
studies and application.