Can app-based devices for pressurized metered-dose inhalers improve asthma outcomes?

In patients using pressurized metered-dose inhalers (pMDIs) for asthma, inhalation technique has been improved through innovative training tools providing audio-visual feedback to patients on correct technique. Use of these app-based devices — namely, the Clip-Tone and the Flo-Tone CR — resulted in better lung deposition of salbutamol, according to results of a study recently published in the Journal of the Science and Technology of Drug Delivery.

Poor technique using pMDIs – especially forced inhalation – leaves the patient with lower drug delivery to the lungs, leading to worse outcomes in adults with asthma. The researchers sought to assess the impact of pMDI add-on devices, namely the Clip-Tone and the Flo-Tone CR, both of which are linked to a smartphone app. As the researchers explain, these add-on devices “produce a hissing sound corresponding to the airflow while [patients are] trying to maintain a slow inspiration. The sounds produced are recognized by their associated smartphone apps and the number of seconds of the inhalation process is displayed on the smartphone screen, giving immediate feedback.

The researchers conducted an experimental crossover study that included 12 healthy adult volunteers (31.1 ± 10.49 years; 73.3 ± 14.48 kg; 50% female). Each participant performed an inhalation via the pMDI alone, then performed an inhalation via the pMDI with the Clip-Tone Add-On Tool and the Flo-Tone CR Add-on Tool (in random order) with washout periods of 48 hours between inhalation procedures. finishes.

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Investigators found the inhalation duration for Clip-Tone to be (5.22 ± 1.07 seconds), similar for Flo-Tone CR and not reported for pMDI alone. Urine samples were collected at 30 minutes to represent pulmonary deposition of salbutamol and at 24 hours to represent systemic bioavailability using the pharmacokinetic model of urinary excretion of salbutamol (in vivo).

Mean measurements revealed a significant increase (P P <.001 half of study participants said they preferred the clip-tone add-on tool two tools were similar and none chose flo-tone cr as their first choice.>

The researchers concluded that “use of advanced training tools that provide audio-visual feedback improved inhalation technique compared to use of pMDI alone, resulting in improved lung deposition of salbutamol. “. They added that the Clip-Tone device did not show superiority in lung deposition of salbutamol over the Flo-Tone CR device.

Limitations of the study include age-related bias, insufficient sample size, lack of randomization for the order of tools used, and inability to measure inhalation duration in pMDI alone.


Sobh AHM, Rabea H, Hamouda MA, Shawky F, Saeed H, Abdelrahim MEA. The impact of using different salbutamol-containing metered-dose inhaler add-ons in healthy adult volunteers: an in vivo study. J Drug Deliv Sci Technol. Published online June 23, 2022. doi:10.1016/j.jddst.2022.103539