Aerosol Science: Technology and Applications

Chapter 10

Pharmaceutical Aerosols and Pulmonary Drug Delivery

Darragh Murnane¹, Victoria Hutter¹, and Marie Harang²

¹Department of Pharmacy, University of Hertfordshire, UK

²Institute of Pharmaceutical Sciences, King's College London, UK

10.1 Introduction

Drug delivery is the science of targeting drug administration to the required site of pharmacological action. The lungs are readily identifiable as a target organ for drug delivery, due to the (relative) ease of access during inhalation. Site-specific delivery of medicaments such as bronchodilators, corticosteroids and anti-infectives directly to their site of action in the airways is an attractive option. Such localised, topical drug delivery maximises a drug's pharmacological effect while limiting systemic exposure and the consequent side effects. Pulmonary drug delivery is by no means a recent phenomenon. As long as 4000 years ago, ancient Indian tribes inhaled vapours for the treatment of obstructed airways (Crompton, 2006). The lung has also long been employed as a systemic portal for drug molecules, albeit not always licitly or therapeutically, as demonstrated by the discovery of tobacco pipes dating back some 2000 years in South America and by Chinese opium inhalers (Sanders, 2007).

The primary physiological function of the lung is to achieve gaseous exchange across the alveoli into the blood circulation. The anatomic characteristics that have evolved to achieve gaseous exchange are the large surface area (>100 m² in the ...