Powder aerosol delivery through nasal high-flow system: In vitro feasibility and influence of process conditions

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

“…Under best case conditions, the maximum dose delivered to a tracheal filter was approximately 20% of the loaded dose. While filter delivered dose was higher in the current study than with Okuda et al (12), a few differences should be noted. First, Okuda et al (12) consider HFNC therapy, where flow rates are typically higher (15 to 40 L/min) compared with 8 to 11 L/min in the current study.…”

“…While filter delivered dose was higher in the current study than with Okuda et al (12), a few differences should be noted. First, Okuda et al (12) consider HFNC therapy, where flow rates are typically higher (15 to 40 L/min) compared with 8 to 11 L/min in the current study. To accommodate these higher flow rates, HFNC systems typically employ larger diameter tubing (~10 mm ID) and larger bore nasal cannula.…”

“…Few studies have attempted the delivery of a powder aerosol through a nasal cannula interface. The most relevant study performed outside of our group is likely Okuda et al (12), who considered a spray dried mannitol formulation delivered during high flow nasal cannula (HFNC) conditions through an adult nasal cast model. Under best case conditions, the maximum dose delivered to a tracheal filter was approximately 20% of the loaded dose.…”

“…With improved delivery devices and formulations, inline DPIs have been tested using in vitro experiments for application to invasive mechanical ventilation (3,7), non-invasive positive pressure ventilation with a face mask (11), and high flow nasal cannula (HFNC) therapy (12). Considering invasive mechanical ventilation, studies by Tang et al (3) and Feng et al (7) have placed the Osmohaler™ containing high dose mannitol powder in a custom chamber and evaluated delivery to the end of endotracheal tubes.…”

“…Using a divided cannula that allowed for simultaneous administration and an excipient enhanced growth (EEG) spray dried formulation of ciprofloxacin, <2% of the aerosol was lost in the nose with lung delivery efficiency in the range of 60% of the loaded dose at mean gas flow rates as high as 30 L/min (LPM). More recently, Okuda et al (12) conducted a systematic analysis of an inline Osmohaler™ applied to a HFNC system. Nasal depositional losses were in the range of 50 to 70% and approximately 10-20% of the loaded dose reached a tracheal filter.…”