Abstract
Dose accuracy and precision for pulmonary drug delivery have been core elements of therapy for asthma for 70 years. As the technology has developed, its application has spread to various diseases. For many inhaled products, solid-state chemistry, the nature of the drug particles, and their relationship to other particles in the formulation underpin success in disease treatment. Methods of manufacturing yield unique particle systems whose properties support the range of doses required to treat diseases with low- and high-potency drugs requiring high and low doses, respectively. To ensure the quality of these particulate products, which correlates with safety and efficacy, comprehensive characterization of their physicochemical properties and aerosol performance is required. The delivered dose and aerodynamic particle size distribution are key characteristics related to lung exposure required in clinical efficacy trials for non-communicable, genetic, environmental, and communicable (i.e., infectious) diseases. The breadth of inhaled therapy has increased significantly since the introduction of the initial products in the last century. The desire to treat genetic diseases, such as cystic fibrosis, and the emergence of new approaches to lung therapy during the COVID-19 pandemic are opening up new opportunities in inhaled biologicals that are anticipated to lead to future developments.