ABSTRACT
The delivery of drugs to the respiratory tract offers considerable advantages over alternative routes of administration. Pulmonary administration is particularly appropriate for drugs having a local action in the respiratory tract, resulting in rapid localized drug action. Moreover, the large alveolar surface area, high vascularity and thinness of the alveolar epithelium, reduced extracellular enzyme levels compared to the gastrointestinal tract, and the evasion of first-pass hepatic metabolism by the absorbed drug offer the potential for pulmonary administration of systemically active materials.
