Lung infections, especially lower respiratory tract infections, are leading causes of death by transmissible diseases worldwide, with the majority of patients having their lungs colonised by different bacteria. These infections tend to have a greater impact on patients who already have existing lung problems such as cystic fibrosis, chronic obstructive pulmonary disease and bronchiectasis.
Unlike oral or intravenous treatments, delivering a drug via the lungs avoids first pass metabolism that happens in the liver. The lungs have low enzymatic activity resulting in less of the drug being metabolised before delivering its therapeutic effect. This means there’s a faster onset of action as the drug is delivered directly to the affected site. In addition, an inhalation method allows the drug to be dispensed in powder form, which reduces any storage stability issues and improves the shelf life.
Current methods to test inhaled antibiotics are based on animal models. The most common animals used are rodents, but they breathe through their nose, so testing oral inhalation on rodents requires drugs to be passed through an unnatural route for their breathing, which does not mimic drug deposition in humans.