INTRODUCTION

The mucosal route of drug administration is subdivided into eight membrane surfaces for the purposes of taxonomic distinction of dosage forms by route of administration. These membrane surfaces are characterized as nasal, ophthalmic, otic, oropharyngeal, pulmonary, rectal, urethral, and vaginal. A drug product may be administered to any of these eight mucosal surfaces to effect either local action or systemic absorption. Local action is to the area proximate to application. Where local action is intended, systemic absorption is not typically desired and is unnecessary for therapeutic effect. In some cases, however, the mucosal delivery of a drug for systemic absorption is used because it avoids first-pass metabolism, it provides more rapid systemic delivery, or it provides an alternative when oral delivery (to the gastrointestinal tract) is not possible due to a disease state. Many of the dosage forms listed in Pharmaceutical Dosage Forms 〈1151〉 can be delivered by way of the various membrane surfaces in the mucosal category.