Flow rate dependence of salbutamol dose with various valved holding chambers in vitro

Inhalation is the primary administration route for managing airway diseases like asthma and COPD. Presently, treatment protocols for management of acute obstruction in emergency care involve using either pressurized metered dose inhalers (pMDI), often with holding chambers (HC), or nebulizers. The aim of this work was to assess the impact of different inhalation patterns and specifically peak inspiratory flow rate (PIF) on drug delivery, as well as to provide a head-to-head comparison between different (HC) in combination with a salbutamol pMDI.

For the comparison we chose two reusable (Vortex and OptiChamber Diamond) and two disposable (DispoZABLE and LiteAire) HCs. The HCs were connected to an anatomical throat model, Next Generation Impactor, and breathing simulator and the deposited drug content was measured with high performance liquid chromatography. In the used inhalation patterns the PIFs were 15 l/min, 30 l/min, 60 l/min, and 80 l/min.

All HCs decreased throat deposition by at least 80%, but throat deposition increased with higher PIF. There was some flow-dependency also in fine particle dose (FPD) but the direction of the dependency varied between the HCs.

The performance of disposable devices in terms of flow dependency and throat deposition was similar to reusable ones.