Near Elimination of In Vitro Predicted Extrathoracic Aerosol Deposition in Children Using a Spray-Dried Antibiotic Formulation and Pediatric Air-Jet DPI

Purpose

This study evaluated the in vitro aerosol performance of a dry powder antibiotic product that combined a highly dispersible tobramycin powder with a previously optimized pediatric air-jet dry powder inhaler (DPI) across a subject age range of 2–10 years.

Methods

An excipient enhanced growth (EEG) formulation of the antibiotic tobramycin (Tobi) was prepared using a small particle spray drying technique that included mannitol as the hygroscopic excipient and trileucine as the dispersion enhancer. The Tobi-EEG formulation was aerosolized using a positive-pressure pediatric air-jet DPI that included a 3D rod array. Realistic in vitro experiments were conducted in representative airway models consistent with children in the age ranges of 2–3, 5–6 and 9–10 years using oral or nose-to-lung administration, non-humidified or humidified airway conditions, and constant or age-specific air volumes.

Results

Across all conditions tested, mouth-throat depositional loss was < 1% and nose-throat depositional loss was < 3% of loaded dose. Lung delivery efficiency was in the range of 77.3–85.1% of loaded dose with minor variations based on subject age (~ 8% absolute difference), oral or nasal administration (< 2%), and delivered air volume (< 2%). Humidified airway conditions had an insignificant impact on extrathoracic depositional loss and significantly increased aerosol size at the exit of a representative lung chamber.

Conclusions

In conclusion, the inhaled antibiotic product nearly eliminated extrathoracic depositional loss, demonstrated high efficiency nose-to-lung antibiotic aerosol delivery in pediatric airway models for the first time, and provided ~ 80% lung delivery efficiency with little variability across subject age and administered air volume.

Read more

Farkas, D., Thomas, M.L., Hassan, A. et al. Near Elimination of In Vitro Predicted Extrathoracic Aerosol Deposition in Children Using a Spray-Dried Antibiotic Formulation and Pediatric Air-Jet DPI. Pharm Res (2022). https://doi.org/10.1007/s11095-022-03316-9