Efficient Nose-to-Lung Aerosol Delivery with an Inline DPI Requiring Low Actuation Air Volume

Abstract

Purpose: To demonstrate efficient aerosol delivery through an in vitro nasal model using a dry powder inhaler (DPI) requiring low actuation air volumes (LV) applied during low-flow nasal cannula (LFNC) therapy.

Methods: A previously developed LV-DPI was connected to a LFNC system with 4 mm diameter tubing. System connections and the nasal cannula interface were replaced with streamlined components. To simulate nasal respiration, an in vitro nasal model was connected to a downstream lung simulator that produced either passive or deep nasal respiration. Performance of a commercial mesh nebulizer system was also considered.

Results: For the optimized system, steady state cannula emitted dose was 75% of the capsule loaded dose. With cyclic nasal breathing, delivery efficiency to the tracheal filter was 53-55% of the loaded dose, which was just under the design target of 60%. Compared with a commercially available mesh nebulizer, the optimal LV-DPI was 40-fold more efficient and 150 times faster in terms of delivering aerosol to the lungs.

Conclusions: The optimized LV-DPI system is capable of high efficiency lung delivery of powder aerosols through a challenging nasal cannula interface.

Keywords: Dry powder inhaler (DPI); inline DPI; low flow nasal cannula; low flow oxygen; nasal cannula aerosol; pharmaceutical aerosol.

Fig. 1:

Schematic of experimental setup showing all major components: LV-DPI, spacer, SL Y-connector, 4 mm tubing, SL cannula, NMT model, filter, LFNC gas flow line, and vacuum/ASL line.

Fig. 2:

Section views showing a) LV-DPI device and b) spacer (LV-DPI outlet connects to spacer inlet).

Fig. 3:

Images of the streamlined components used in the study: a) Y-connector, b) Original Cannula (with circular nasal prongs), and c) Cannula 2 (with elliptical nasal prongs).

Fig. 4:

Images of a) NMT internal geometry and b) NMT external surfaces.

Fig. 5:

Graphs showing the two breathing profiles used in this study: a) Passive Nasal inhalation and b) Deep Nasal inhalation

Fig. 6:

Picture of experimental setup showing all major components: air syringe, LV-DPI, spacer, SL Y-connector, 4 mm tubing, SL cannula, NMT model, filter, LFNC gas flow line, and vacuum/ASL line.