Controlled Drug Delivery via the Buccal and Sublingual Routes

This chapter reviews a description of conventional, advanced, and novel dosage forms and controlled delivery systems followed by key excipients and their influence in dosage form performance with updated research. Drugs administered through either the buccal or sublingual mucosa are exposed first to saliva and mucus, and face the respective epithelial barriers before reaching capillaries in the basal lamina and from there are drained onto the jugular vein and to systemic circulation. Saliva and salivary secretion are the amount of fluid available for dosage form and drug dissolution and as such, they are key in the outcome of the permeation strategy and bioavailability. One key feature of buccal or sublingual controlled delivery systems is their functionalization of directed release. Permeation enhancers have been widely studied and reported as means to improve bioavailability of poorly permeable drugs including biologics. Mucoadhesive polymers have been used for years in developing films and coatings for buccal solid dosage forms.