Advances in Drug Delivery from Nose to Brain: An Overview

Brain targeting has always been challenging due to the presence of various physiological barriers resulting in low bioavailability via the oral and parenteral route. Altering the integrity of these barriers so as to permit the drugs to enter into the brain could severely damage the Central Nervous System by also allowing the entrance of toxic substances, bacteria and viruses into the brain. This problem can be tackled by delivering drugs via the intranasal route which bypasses the blood brain barrier and reaches different parts of the brain primarily via the olfactory and trigeminal neural pathways. This route offers several advantages over the oral and parenteral route and has shown potential for targeting drugs to the brain for treating various central nervous system disorders such as Psychosis, Parkinson's and Alzheimer's disease. In spite of several advantages, the intranasal route faces many challenges. Hence, a complete understanding of every aspect related to nose to brain delivery is of utmost importance. This article reviews the mechanism of nose to brain drug transport, challenges and approaches for nose to brain drug delivery, a few specialized olfactory delivery devices and some applications of this novel route of brain targeting.