The mucosal layer represents a potential site for the attachment of bio-adhesive drug delivery systems, as it lines several parts of the body such as the gastrointestinal tract, urogenital tract, vaginal tract, eyes, ears, and nose. Among these, oral transmucosal drug delivery has gained more attention compared to other mucoadhesive systems like vaginal, rectal, nasal, and ocular delivery. The buccal mucosa, in particular, is rich in vascular and lymphatic systems, which allows drugs to be absorbed directly into the systemic circulation, bypassing the first-pass metabolism in the liver and avoiding pre-systemic elimination in the gastrointestinal tract. Moreover, buccal drug delivery can be quickly discontinued in case of toxicity, making it a safer and more convenient method of drug administration. This system takes advantage of the physicochemical properties of both the drug formulation and the mucosal lining. It's important to note that the mucoadhesive properties of a dosage form are only effective on moist surfaces.