Mucosal drug delivery: membranes, methodologies, and applications.

In recent years, extensive research into novel forms of drug delivery has suggested that mucosal approaches offer a promising therapeutic alternative, especially for systemically acting drugs. Transmucosal drug delivery offers many benefits, including noninvasive administration, convenience, rapid onset, as well as elimination of hepatic first-pass metabolism. The investigated absorptive surfaces consist of the nasal, buccal, ocular, vaginal, and rectal mucosae. Among these, the nasal and buccal routes have proved the most promising to date. The bioavailability achieved mainly depends upon the pathophysiological state of the mucosa and the properties of both the drug and delivery systems. Various agents can increase the efficacy of transmucosal drug delivery. These include cyclodextrins, bile salts, surfactants, fusidic acid derivatives, microspheres, liposomes, and bioadhesive agents. The mechanisms of action, effectiveness, and toxicity profiles of these enhancers have been investigated extensively in both animal and human models.