Abstract
Recently, the nasal route for systemic drug delivery has gained great interest. It provides several advantages over other routes of drug administrations. These include rapid absorption, avoidance of the intestinal and hepatic presystemic disposition, and high potential for drug transfer to the cerebrospinal fluid. Unfortunately, the mucociliary clearance, which reduces the residence time of the nasally applied drugs, and the poor nasal permeability made it difficult for many drugs to be delivered through this route. Alternative approaches have been adopted to overcome these problems. These include the use of mucoadhesive formulations or chemical penetration enhancers. Vesicular drug delivery systems provide promising alternative for enhanced and controlled nasal drug delivery.
Alternative terms have been used to describe the vesicular systems. These include liposomes, niosomes, ethosomes, and transfersomes. These systems arc morphologically similar but differ in composition and function. Nasal delivery employs liposomes and niosomes, and their corresponding proconcentrates, proliposomes and proniosomes. Encouraging results have been recorded for these systems after nasal application with the possibility of achieving many objectives such as systemic delivery of small and large molecular weight drugs. This review article discusses such systems for intranasal vaccination and for improvement of nasal drug delivery to the central nervous system. The review critically evaluates the potential of such systems for systemic drug delivery after intranasal applications.