Strategies to overcome the barriers to effective inhaled treatments

This Research Topic focuses on novel strategies for improving inhaled drug delivery. Formulation, inhaler device, and patient are the three important aspects that affect pulmonary drug delivery and are therefore important considerations in the development of inhaled treatments. Factors that relate to them can render aerosolisation and/or pulmonary deposition suboptimal. Inhaled drug delivery is challenging because, unlike the more “conventional” routes of administration (such as oral or intravenous delivery), the generation and fate of aerosols depend on many factors. For example, aerosolisation efficiency of a powder may be influenced by the formulation (e.g. particle size, interparticulate cohesion), inhaler device (e.g. geometry, airflow resistance, aerosolisation mechanism), and patient (e.g. peak expiratory flow rate, pressure drop generated). Furthermore, potential interactions between multiple factors will make prediction of aerosol performance and treatment outcome even more difficult. For instance, the effect of the proportion of a certain excipient in a powder may be affected by the design of the inhaler device. Patient factors such as their inhaler technique, inhalation profile, and throat deposition are also sources of variability and potential barriers to effective treatment. Thus even a supposedly excellent inhaled product may not offer optimum treatment if the patient does not use it properly or consistently. Dissolution is another barrier, especially for hydrophobic drugs, because the amount of airway fluid available for drug dissolution is quite low. The drug concerned would then need to be formulated to enhance its solubility. The diverse problems mentioned above reflect the broadness of this Research Topic, the ultimate goal of which is to explore how problems in inhaled drug delivery can be solved to optimize treatment.

Keywords: Aerosol, Inhalation, Pulmonary delivery, Lungs, Particles

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