Mucosal delivery

Mucosal delivery is the absorption of a compound through the moist lining of the mouth, nose, rectum or vagina rather than through the digestive tract or skin.

Mucous membranes are thin, well supplied with blood vessels and lack the tough outer keratin layer of skin, so suitable molecules can pass into the bloodstream quickly. Sublingual and buccal formats place a tincture, spray, film or lozenge against the oral mucosa and hold it there; nasal sprays use the nasal lining; and suppositories use the rectal or vaginal mucosa. Each route avoids first-pass metabolism in the liver to a degree, which can raise bioavailability and speed onset compared with swallowing.

In practice, much of a sublingual cannabinoid serving is eventually swallowed, so the real absorption is a mix of mucosal and oral. Formulation matters: fat-soluble cannabinoids in an oil carrier cross mucosa slowly, which is why some products use emulsifiers or nanoemulsions. Mucosal delivery is also why the condition of the oral tissues, and the flavorings and alcohol content in a product, are relevant to comfort and irritation.