In vitro evaluation of nonconventional accessory devices for pressurized metered-dose inhalers

Ann Allergy Asthma Immunol. 2014 Jul;113(1):55-62. doi: 10.1016/j.anai.2014.04.006. Epub 2014 May 9.


Background: The selection of accessory devices for pressurized metered-dose inhalers (pMDIs) by health care professionals is typically cost driven without consideration of how the device modifies clinical outcomes.

Objective: To evaluate nonconventional accessory devices and the open-mouth technique with and without ideal coordination of actuation and inhalation to identify and understand the considerations for recommending potential inexpensive devices.

Methods: In vitro performance parameters of the beclomethasone dipropionate pMDI were evaluated with several devices (AeroChamber, toilet paper roll, paper towel roll, rolled paper, plastic bottle spacer, bottle-holding chamber, and nebulizer reservoir tubing).

Results: Compared with the pMDI alone, all the accessory devices evaluated have significantly lower drug exposure and throat deposition and higher respirable fractions, with the paper towel roll having the greatest effect of the devices evaluated (exposure decreased from a mean [SD] of 76.1 [4.8] μg to 49.2 [2.0] μg, throat deposition decreased from 32.0 [3.2] μg to 0.8 [0.3] μg, and respirable fraction increased from 49.8% [3.2%] to 96.4% [0.4%]). Introduction of a delay between actuation and inhalation resulted in greater variability in performance metrics for the devices evaluated, and the bottle-holding chamber and paper towel roll were most effective in mitigating the effect of the delay. The open-mouth technique was found to decrease throat deposition and respirable mass compared with the pMDI alone.

Conclusion: In addition to cost, the amount of drug that deposits in the throat and the lungs and the effect of asynchronous actuation and inhalation can vary with the selection of an accessory device, which may affect the therapeutic benefits of the pMDI selected.

MeSH terms

  • Administration, Inhalation
  • Anti-Asthmatic Agents / chemistry*
  • Beclomethasone / chemistry*
  • Humans
  • Metered Dose Inhalers / classification*
  • Metered Dose Inhalers / economics
  • Models, Anatomic*
  • Particle Size


  • Anti-Asthmatic Agents
  • Beclomethasone