The advantages of designing high-resistance swirl chambers for use in dry-powder inhalers

Guy Furness, the publisher at ONdrugDelivery Magazine introduced the article with the following abstract:

“In this article, David Harris, Head of Respiratory Drug Delivery, Team Consulting, taps into a powerful combination of detailed anatomical and functional understanding of the human respiratory system, pulmonary drug delivery technology and formulation expertise, and mathematical modelling techniques, in order to put forward the case for high-resistance swirl chambers in dry-powder inhalers, and a rational strategy for optimising the design and thus maximising therapeutic efficacy.”

Why is high resistance good from a patient’s perspective?

The question dry powder inhaler (DPI) device developers always face is “What airflow resistance should I make the device?”. Many studies have been conducted and the results often published, but there still appears to be no commonly agreed answer about what is best. The airflow resistance of the pressurised metered dose inhaler (pMDI) is rather arbitrary, as pMDIs produce a respirable aerosol completely independently of how the user inhales. DPIs, on the other hand, rely solely upon the energy available in the user’s inspiratory manoeuvre – some of which is transferred into the bulk powder to transform it into a respirable aerosol.

There are several performance factors that are directly affected by the resistance of a DPI.

This article was published in issue 57 of ONdrugDelivery Magazine and written by David Harris, Head of Respiratory Drug Delivery.

David heads up Team’s respiratory drug delivery sector, applying solid aerosol science and fluid dynamics to improve the efficacy of inhaler technology.