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Reviving Positive Pressure DPIs for Efficient and Reproducible Aerosol Delivery to Infants and Children

Longest P, Farkas DR, Bass K, Howe C, Boc ST, Momin M, Dhapare S, Hassan A, Bonasera S, Hindle M.

Respiratory Drug Delivery 2020. Volume 1, 2020: 71-80.

Abstract:

This review initially compares the performance of a number of positive pressure dry powder inhalers (DPIs) that have been developed over the last two decades. A key observation is that DPI aerosolization performance is significantly increased with devices designed specifically for positive pressure actuation and when these devices are developed in combination with highly dispersible spray-dried powder formulations. Of the positive pressure devices reviewed, the new air-jet based design is shown to perform well across both high and low actuation air-volumes. The review then describes the air-jet DPI in more detail, and illustrates prediction of device aerosolization performance using computational fluid dynamics (CFD)-based dispersion parameters. Interestingly, reducing turbulence within the air-jet DPI is observed to have the beneficial effect of also reducing the mass median aerodynamic diameter (MMAD) of the aerosol. This finding is unique to the air-jet DPI design and has important implications for also reducing downstream depositional losses. An initial study is then summarized in which the air-jet DPI is demonstrated to provide high and consistent aerosol delivery through a pediatric (5-year-old) nose-throat in vitro geometry.