Summary:-: Summary:- The concept of bioadhesion involves the binding of a natural or synthetic , bioadhesive polymer to biological substrates such as mucous membranes. Bioadhesive drug delivery systems have been available since the late 1940s and have become an important route of delivering drugs. The earlier applications of bioadhesive formulations mainly involved the oral cavity and the gastrointestinal tract. These days bioadhesive drug delivery systems have been developed to target a wider variety of mucosal and epithelial surfaces, these include the vagina, the skin and the nasal cavity. In most instances bioadhesive formulations are preferred over the conventional methods of drug delivery. This is because Bioadhesion allows the retention of the active drug over the mucosal surface and prolongs the contact time between the polymer and mucosal surface. Bioadhesive drug delivery also offers a controlled release of drugs. From a patient’s point of view this is ideal because the frequency of drug administration is reduced which in turn improves patient compliance.