Nasal Drug Delivery System-Factors Affecting and Applications

Abstract: The nasal route is a potential alternative route for systemic availability of drugs restricted to intravenous ad-ministration, such as peptide and protein drugs and vaccines. This route is also advisable for drugs undergoing extensive first pass effect .Besides this, intranasal route has also been successfully exploited for bypassing the blood brain barrier [BBB] and subsequently delivering drug molecules to central nervous system [CNS]. The present article highlights the advantages, barriers, physicochemical factors and formulation related parameters affecting the nasal drug delivery. It also includes a note on nasal absorption enhancers. Also, the applications of nasal route for delivery of peptides and proteins, non-peptide drugs, vaccines and drug molecules to CNS have been summarized in depth. Key Words : Nasal route, nasal absorption enhancers, peptide, protein drugs, vaccines, central nervous system. INTRODUCTION The nasal mucosa has been considered as a potential ad-ministration route to achieve faster and higher level of drug absorption. This is due to the large surface area, porous en-dothelial membrane, high total blood flow, the avoidance of first-pass metabolism, and ready accessibility. The nasal administration of drugs, including numerous compounds, peptide and protein drugs, for systemic medication has been widely investigated in recent years. In the recent past many researchers have also attempted delivery of drugs to the CNS through the nose. However, the major limitation with nasal route administration is the poor contact of the formulations with the nasal mucosa. Many attempts have been made in the recent past to increase the residence time of drug formula-tions in the nasal cavity, resulting in improved nasal drug absorption. Researchers became interested in the nasal route for the systemic delivery of medication due to high degree of vascularization and permeability of the nasal mucosa. Several researchers have studied the anatomical and physiological aspects of the nasal membrane, including its vascular nature, as they relate to drug delivery[1-8]. The nose is divided into two nasal cavities