What does 'buccal' refer to in the context of drug administration?

In the context of drug administration, 'buccal' specifically refers to the use of mucous membranes for drug delivery. This method involves placing a medication between the gums and the inner lining of the cheek, where it can dissolve and be absorbed into the systemic circulation through the oral mucosa. This route allows for a bypass of the digestive system and first-pass metabolism in the liver, enabling quicker therapeutic effects and increased bioavailability for certain medications.

The other options describe distinct routes of drug administration: intravenous (via the veins), intramuscular (injection into the muscle), and oral administration (via swallowing), but none refer specifically to the buccal route, which is characterized by its unique delivery method through the buccal mucosa. Thus, the correct association of 'buccal' with mucous membranes makes it clear how this particular route functions in drug delivery.