Inhalation Drug Therapy: Emerging Trends in Nasal and Pulmonary Drug Delivery

The success of drug therapy is highly dependent on route of administration, and oral route of administration is the most successful, popular, and patient friendly. However, the bioavailability of many drugs is less due to first-pass metabolism which paved a way for development of innovative drug formulations and routes of administration. Biologics and antineoplastic therapeutics are restricted to parenteral route only due to bioavailability issues in other routes of administration which often leads to off-target toxicities; therefore inhalational route for therapeutic delivery has been gaining attention recently to enhance bioavailability by taking advantage of rich blood supply of lungs. This route is used for delivering agents locally to the lungs during diseased states such as chronic obstructive pulmonary disease, asthma, or cystic fibrosis. It also acts as a portal to access blood and lymphatic systems. Nasal route has been explored since the beginning of human civilization, and Indian Ayurvedic system of medicine uses this route since long. Rapid onset of action of systemically acting products is an important advantage. The present chapter covers factors affecting absorption, drug repositioning strategies, characterization tests, and clinical trials of nasal as well as pulmonary therapeutics.