The term “buccal” is an anatomical descriptor derived from the Latin word bucca, meaning cheek. It refers specifically to the cheek or the inside of the mouth. This term is used consistently across anatomy, dentistry, and medicine to precisely locate structures or describe procedures. In medicine, it often refers to the inner lining of the cheek, a location increasingly used for administering medications.
Defining the Buccal Region
The buccal region encompasses the inner surface of the cheek, which is lined by a specialized tissue called the buccal mucosa. This mucosa is a smooth, moist membrane that forms the interior boundary of the oral cavity. It covers the cheek muscles and rests adjacent to the teeth and gums, forming the buccal vestibule.
In dentistry, the term provides a directional reference for surfaces facing the cheek, such as the buccal surface of a back tooth. This surface is distinct from the lingual surface, which faces the tongue, or the labial surface, which faces the lips. The region also contains the buccal fat pad, a mass of fatty tissue providing cushioning and contour to the cheek. The buccal mucosa is highly vascularized, containing a dense network of small blood vessels close to the surface.
Drug Delivery Through the Cheek
The rich blood supply of the buccal mucosa allows it to serve as an effective route for systemic drug administration, known as buccal drug delivery. When medication is placed in the buccal pouch (between the cheek and the gum), drug molecules diffuse directly through the lining into the capillaries. This transfer allows the medication to quickly enter the bloodstream and circulate throughout the body.
A major advantage of this method is its ability to bypass first-pass metabolism. This process significantly reduces drug concentration when medications are absorbed through the stomach and intestines. Orally swallowed drugs travel to the liver, which metabolizes a portion of the drug, decreasing its bioavailability before it reaches the rest of the body.
Buccal delivery avoids the gastrointestinal tract entirely, allowing a higher concentration of the active drug to reach systemic circulation. This often results in a faster onset of action. This method is useful for drugs easily degraded by stomach acid or extensively metabolized by the liver, such as certain opioids and hormones. Dosage forms commonly used include small tablets, films, or patches that adhere to the mucosa and slowly release the medication.
Buccal delivery is functionally similar to sublingual delivery, where a drug is placed under the tongue, but differs in the exact placement within the mouth. The buccal mucosa is thicker and less permeable than the thin lining under the tongue. This makes the buccal route more suitable for sustained-release formulations, allowing steady absorption over a longer period. The sublingual route is typically reserved for drugs requiring a rapid spike in blood concentration, such as nitroglycerin.