Mucoadhesive drug delivery systems have several advantages over oral controlled drug delivery systems. Some of these advantages are prolongation of residence time, drug targeting, intimate contact between dosage form and absorptive mucosa. Mucoadhesive formulations use polymers as an adhesive component. These polymers are water soluble but when they are used in dry form they attract water from mucosal surface and produce adhesive interactions. These dosage forms are readily localized in the region applied to improve and enhance the bioavailability of drugs. Mucoadhesive dosage forms also prolong residence time of the dosage forms at the site of application and absorption to permit once or twice a day dosing.