ABSTRACT
For systemic drug administration, the nasal route appears to be an ideal alternative to use of the parenterals, especially in view of the rich vascularity of the nasal mucosa and the ease of intranasal drug delivery. An important aspect of nasal drug delivery is the effect of drugs and additives on nasal ciliary functions; indeed, among drugs and additives found to have a negative effect are preservatives, antihistamines, propranolol, bile salts, cocaine, xylometazoline, atropine, and hairspray. The vehicle for nasal formulations and mode of application may be optimized to deliver drugs to the absoptive turbinate region. Long-term use of an absorption enhancer and chronic use of an enhancer-containing nasal formulation will affect nasal functions and thus the efficiency of nasal absorption. It is important to investigate the pathways for nasal absorption before nasal delivery rate and transnasal bioavailability of drugs can be improved and controlled.
