Drugs delivered by inhalation are used to treat various human illnesses. Several inhalation-based drug delivery systems exist: liquid nebulisers, aerosol-based metered dose inhalers, and dry powder dispersion devices. Such devices aim to deliver drugs to the lungs, so they can be either distributed throughout the body via the alveolar epithelium and the blood circulatory system, or deposited locally to the central bronchioles. Interest has recently shifted towards spray-dried powders, in an effort to decrease oropharyngeal deposition, increase fine particle fraction and achieve modified release of one or more drugs.

Scientists in the Aston Pharmacy School have discovered that the combination of an amino acid and a biodegradable polymer can achieve these goals. The formulation utilises Chitosan, a pharmaceutically acceptable biodegradable polymer used to sustain drug release, and Leucine, an essential amino acid used as an aerosolisation enhancer. Spray-dried powders manufactured with these components display modified release of the active agent and improved dispersibility.