Complexity in pharmaceutical powders for inhalation

Abstract

Pharmaceutical aerosol powders intended for inhalation are required to have unique performance characteristics that are highly dependent on their physico-chemical properties. A wide range of analytical methods have been applied to study particle structure, size distribution, surface properties and subsequent behaviour of powders with the intention of predicting their performance. However, particle interactions are dictated by complex fundamental forces that impact on the efficiency and reproducibility of delivery and thereby the quality, efficacy and safety of the final product. This manuscript reviews the interplay of physico-chemical properties of powder and the complex process and analytical variables that must be monitored and controlled to effectively predict powder performance.