sublingual delivery

Sublingual delivery means placing a dosage form under the tongue and letting it dissolve so the drug is absorbed there, very fast, straight into the bloodstream. The floor of the mouth is thin and richly supplied with blood vessels, so it acts almost like an express lane for drugs that need to work in a hurry.

Because the sublingual mucosa is thin and highly vascular, suitable drugs reach the blood within minutes, and like the buccal route they drain into the general circulation, bypassing the gut and the liver's first-pass metabolism. This makes sublingual administration ideal for emergencies and for drugs that would be largely destroyed if swallowed. Dosage forms are designed to dissolve quickly: sublingual tablets, sprays, films, and fast-melting lyophilized wafers.

The trade-off is that the very feature giving speed — rapid washout by saliva and the urge to swallow — also limits how long drug stays in contact, so sublingual delivery suits potent, fast-dissolving, reasonably permeable drugs in small doses rather than slow or sustained dosing. Patients must also be coached not to swallow or eat and drink immediately, and not all drugs are permeable enough to use this route.