The lungs possess many xenobiotic metabolizing enzymes which influence the pharmacokinetics and safety of inhaled medicines. Anticipating metabolism in the lungs provides an opportunity to optimize new inhaled medicines and overcome challenges in their development.

Antifungal drugs administered via the pulmonary route for aspergillosis are absorbed through the lung tissues, where they may undergo limited metabolism. The primary metabolism occurs in the liver after systemic absorption, and excretion is mainly through the kidneys and feces. Pulmonary delivery can enhance the drug's efficacy at the site of infection while minimizing systemic side effects.