Atul Kumar

There are various approaches for the delivery of therapeutic substance to the target site in a controlled release fashion. One such approach is using microspheres as carriers for drugs or active pharmaceutical compound. However, the success of this drug delivery system is limited due to their short residence time at the site of absorption. Mucoadhesive microspheres can be tailored to adhere to any mucosal tissue including those found in stomach, thus offering the possibilities of localized as well as systemic controlled release of drugs. This article presents the  advantages of Mucoadhesive microsphere, mechanism, theories involved in mucoadhesion, factor that affect the mucoadhesion, polymer in Mucoadhesive drug delivery system, methodology of preparation of Mucoadhesive microsphere, method of evaluation and their applications in drug delivery. Mucoadhesive drug delivery systems promises several advantages that arise from localization at a given target site, prolonged residence time at the site of drug absorption and an intensified contact with the mucosa increasing the drug concentration gradient.

The aim of writing this review is to put a light on the recent trends in development of Drug loaded Beads. Drug loaded beads are gastro retentive drug delivery systems based on multi Unit approach and are prepared to obtain prolonged or controlled drug delivery, to improve bioavailability, stability and target drug to specific sites. These are Spherical in shape and approximately 1.5 mm in diameter. These can be prepared by various methods like ionotropic gelation, hydrogel embedment, solvent evaporation and Melt Solidification by using different polymers. Promising enhancement in bioavailability and site specificity has been achieved by drug loaded beads.