The Impact of Device Handling Errors upon Inhaled Medication Delivery from Pressurized Metered Dose Inhalers (pMDIs) Used with and without a Valved Holding Chamber (VHC)  

Jason A Suggett¹, Mark W. Nagel¹ & Jolyon Mitchell²

¹Trudell Medical International, 725 Third Street, London, Ontario, NV5 5G4, Canada

²Jolyon Mitchell Inhaler Consulting Services Inc., 1154 St. Anthony Road, London, N6H 2R1, Canada

Summary

Evaluations of inhaler use have demonstrated that patient mishandling of pMDIs is commonplace. This study investigated the potential impact on medication delivery associated with three errors: (a) delayed inhalation, (b) over-forceful inhalation, and (c) exhalation instead of inhalation at the time of pMDI actuation. The large adult Aerosol Delivery to an Anatomic Model (ADAM) model oropharyngeal airway was used to determine the penetration of pMDI-delivered salbutamol (Ventolin^Ò-HFA, 100-mg salbutamol base equivalent/actuation) to a distal filter representing potential lung delivery.  AeroChamber Plus^Ò Flow-Vu^Ò antistatic devices with mouthpiece (n = 3 devices, 1 measurement per device) were used as the test VHC. Delaying inhalation by 1-s resulted in a decrease of 80% in the mass penetrating as far as the filter compared to optimal no delay for the pMDI alone. When the VHC was present, the mass of salbutamol reaching the filter after a 2-s delay was comparable with optimum delivery of medication from the pMDI alone and further delays up to even 15-s resulted in less than 40% reduction. When a forceful inhalation was simulated, filter-collection of salbutamol for the pMDI alone and pMDI with VHC were both reduced in the order of 20-30% compared to the slow inhalation condition with the same configuration. No medication was collected on the filter when exhalation took place upon pMDI actuation when used alone. Adding the VHC resulted in filter collection comparable to the mass delivered under normal inhalation with a 2-s delay.