Advances in inhaled technologies: understanding the therapeutic challenge, predicting clinical performance, and designing the optimal inhaled product.

Inhaled medicines are designed mainly to provide safe and efficacious treatment of respiratory diseases, offering the potential advantages of targeted drug delivery such as reduced onset time and increased therapeutic ratio. However, as a flipside of targeted drug delivery, drug levels in the relevant effect compartment cannot be easily assessed. In combination with technical challenges associated with aerosolizing and administering an inhaled medicine, this renders inhalation product development demanding in the regulatory aspect as well. Emerging technologies that could address some of these challenges include (i) mechanistic pharmacokinetic/pharmacodynamic (PK/PD) modeling, which in combination with experimental techniques such as positron emission tomography could provide information on local target engagement; (ii) patient-feedback features in combination with electronic monitoring, which may improve patient adherence as well as patient handling; and (iii) controlled-release formulations and nanotechnology-based formulations with high drug load, which may expand the scope of development of compounds and targets suitable for inhalation product development.