Dry Powder Inhaler Delivery of Tobramycin in In Vitro Models of Tracheostomized Children

Background: Pediatric tracheostomies are not uncommon and aerosols allow for targeted lung therapy. However, there is little literature that quantifies aerosol delivery through tracheostomies. Nebulizers are commonly used in delivering tobramycin, but there are drawbacks, for example, time burden. Dry powder inhalers (DPIs) can deliver higher payloads in less time. However, no data exist assessing DPIs with tracheostomies. Objective: The study's aim was to quantify the amount of aerosolized tobramycin delivered to the lungs of in vitro tracheostomized spontaneously breathing pediatric models with the TOBI^® Podhaler™ (Podhaler) and the PARI LC Plus^® (LC Plus). Methods: In vitro tracheostomized models of a 6- and 12-year-old trachea were created. Tobramycin aerosol was delivered to the models using either the LC Plus or Podhaler and captured on a filter at the trachea's distal end. A colorimetric tobramycin assay was used to quantify the amount. Three devices of each type were tested in triplicate to ensure repeatability. Results: A total of 36 runs were completed and showed that the Podhaler was more efficient compared with the LC Plus. Mass and percentage of nominal dose, mean ± standard deviation (LC Plus vs. Podhaler with single capsule), was 72.4 ± 11.1 mg (24.1% ± 3.7%) versus 24.2 ± 2.4 mg (86.6% ± 8.7%); p < 0.001. Conclusions: The study's results show that the Podhaler was significantly more efficient compared with the LC Plus, and three Podhaler capsules delivered approximately the same amount of drug as the Tobramycin inhalation solution. These results suggest that Podhaler's tobramycin delivery is a feasible option in tracheostomized pediatric patients and a clinical study is warranted.