Buccal mucosa

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.

Buccal administration of drug provides a convenient route of administration for both systemic and local drug actions. The preferred site for retentive oral transmucosal delivery systems and for sustained and controlled release delivery device is the buccal mucosa. Rapid developments in the field of molecular biology and gene technology resulted in generation of many macromolecular drugs including peptides, proteins, polysaccharides and nucleic acids in great number possessing superior pharmacological efficacy with site specificity and devoid of untoward and toxic effects. However, the main impediment for the oral delivery of such drugs as potential therapeutic agents is their extensive presystemic metabolism, instability in acidic environment resulting into inadequate and erratic oral absorption. Direct access to the systemic circulation through the internal jugular vein bypasses drug from the hepatic first pass metabolism leading to high bioavailability. The objective of this article is to review the developments in buccal adhesive drug delivery system as patches.

  Buccal mucosa is the preferred site for both systemic and local drug action. The mucosa has a rich blood supply and it relatively permeable. Mucoadhesion can be defined as a state in which two components, of which one is of biological origin, are held together for extended periods of time by the help of interfacial forces. Mucoadhesion is a complex phenomenon which involves wetting, adsorption and interpenetration of polymer chains. Buccal mucoadhesive systems remain in close contact with the absorption tissue, the mucous membrane releasing the drug at the action site leading to increase in bioavailability (both local and systemic effects). Extending the residence time of a dosage form at a particular site and controlling the release of drug from the dosage form are useful especially for achieving controlled plasma level of the drug as well as improving bioavailability. In the present review article discusses with the buccal membrane, theory and kinetics behind buccal mucoadhesion, different types of buccal formulation advantages and disadvantages of buccal mucoadhesive drug delivery system.