Abstract: 
Drug actions can be improved by developing new drug delivery systems; one such formulation being a mucoadhesive system. These systems remain in close contact with the absorption tissue, the mucous membrane, releasing the drug at the action site leading to increased bioavailability for both local and systemic effects. Over the last few decades, the application of mucoadhesive polymers in nasal drug delivery systems has gained interest among pharmaceutical scientists as a means of promoting dosage form residence time in the nasal cavity as well as for improving intimacy of contact with absorptive membranes of the biological system. In addition, the enhanced paracellular absorption following the swelling of the mucoadhesive polymers on the nasal membranes provides an important way for the absorption of the macromolecules through the nasal cavity. This review describes some aspects of mucoadhesion related to the nasal drug delivery system. On the first count, the theories of the adhesion of mucoadhesive polymers to the mucosa epithelium are described. Secondly, the characteristics and application of several widely used mucoadhesive polymers in nasal drug delivery are presented. The mucoadhesive polymers have enormous potential for the delivery of therapeutic macromolecules, genes, and vaccines through the nasal cavity with enhanced bioavailability.

Keywords: Mucoadhesion, Mucoadhesive Polymers, Mucociliary Clearance, Nasal Drug Delivery, Absorption Enhancers.