Abstract
Drug development technologies constituting innovations at the formulation end in the pharmaceutical industry has received a lot of attention in past two decades. Drug delivery as an opportunity to extend product life cycles has indeed proved its place in the market with
significant advantages of therapeutic gains as well as commercial success. Carrier technology offers an intelligent approach for drug delivery by coupling the drug to a carrier particle such as microspheres, nanoparticles, liposomes, etc. which modulates the release and absorption characteristics of the drug. Mucoadhesion is a topic of current interest in the design of drug delivery systems. Mucoadhesive microspheres exhibit a prolonged residence time at the site of application or absorption and facilitate an intimate contact with the underlying absorption surface and thus contribute to improved and/or better therapeutic performance of drugs. Hence, uptake and consequently bioavailability of the drug is increased and frequency of dosing reduced with the result that patient compliance is improved. In recent years such Mucoadhesive microspheres have been developed for oral, buccal, nasal, ocular, rectal and vaginal for either systemic or local effects. This review article aims to provide various aspects of mucoadhesion, theories of mucoadhesion and the polymers which will shows the excellent mucoadhesive properties. It also contains a number of available methods of preparation of microspheres and its evaluation including in vitro-wash off test for to determine the mucoadhesive property of prepared microspheres.

Key words: Mucoadhesion, Mucoadhesive polymers, Microspheres, Controlled drug delivery