Investigations to achieve improved aerosol deposition profiles from dry powder inhalers

Asthma andchronic obstructive pulmonary diseaseaffect 6 % of the population in the UK causing high numbers of deaths. Therefore, in the last 40 years, metered dose inhalers (MDIs) and dry powder inhalers (DPIs) have been employed and developed. However, due to an inefficient inhalation technique, many adults and children received a low dose of the drug. DPIs offer many avantages over MDIs in the absence of required “hand-lung” coordination issues. However, they are highly susceptible to variations in patients' lung strength and inspiratory profiles. As a result there is substantial variability in the lung deposition profiles obtained with DPIs and there is also substantial waste of potentially effective drug due to throat deposition. In this project, we will attempt to identify the link between inhalation profiles through devices, formulation type and device design and the clinical effect of therapies. We will also examine attempts to mitigate the inhalation flow dependence of commercial DPIs through device engineering approaches.

We have developed and tested a prototype using a novel concept spacer with dry powder inhalers to achieve flow-rate independent drug delivery.

We have established a testing method to allow for rapid screening of patient inhalation profiles through DPI devices, suitable for use in respiratory clinics.

We are now looking at the role of powder structure on the effectiveness of the spacer device.

We are currently seeking ethical approval for a study within the National Health Service to identify the links between asthma control and inhalation profiles through DPIs.