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The impact of different valved holding chambers (VHCs) on lung drug delivery: using functional respiratory imaging (FRI) and a single metered dose inhaler (MDI) type

Rationale: One of the most common MDI use errors is the failure to coordinate inhalation with inhaler actuation. VHCs are often prescribed to reduce the severity of this error. This FRI based study assessed different VHCs, comparing their impact on modelled lung delivery, in addition to MDI used alone. Methods: 3D geometries of airways and lobes were extracted from a CT scan of a 67 year old male COPD patient. Drug delivery and airway deposition of MDI delivered albuterol was modelled using FRI with measured particle and plume characteristics with and without three VHCs (AeroChamber Plus Flow-Vu, ACPlusFV; OptiChamber Diamond, OD; Compact Space Chamber Plus, CSCP). For the MDI alone a ‘perfect coordination’ 0 second delay and a 9short inhalation9 0.5 second delay were evaluated. For the MDI/VHC systems a typical 2 second delay was evaluated. Results: The deposition profile results are shown in table (mcg).
 Conclusions: The FRI profiles highlighted significant differences between the VHCs on test, with intrathoracic delivery for the AeroChamber Plus Flow-Vu VHC system being almost double that of the other two VHC systems and being similar to the MDI alone with perfect coordination. The almost complete removal of intrathoracic delivery with a short inhalation delay with MDI highlights the advantage of using a VHC.