A perspective on synthetic and solid-form enablement of inhalation candidates

The administration of compounds by a dry-powder inhaler presents significant challenges to the development and discovery chemist, owing to the stringent requirements placed upon the physical characteristics of the active pharmaceutical ingredient and the high complexity of the molecules concerned. The current state of synthetic chemistry technology is such that commercial syntheses of these compounds are demanding but achievable. While synthetic chemistry will remain a major component of the development of inhaled therapies, the main challenge facing practitioners in this area is the early identification of a suitable solid form. Further advances in the prediction of solid-form properties would significantly enable this field and may allow triage of molecules to be carried out at the design stage of projects.