Patient centric optimization of a successful soft mist inhaler

Introduction: The Respimat Soft Mist^™ inhaler, a propellant-free, pocket-sized device generating an inhalable aerosol, was designed to enhance drug delivery to the lungs, reduce the requirements for patient coordination and inspiratory effort, and improve patientsʼ experience and ease of use. Recent updates to the device have focused on making the Respimat more patient-friendly in terms of handling and ease of use, while maintaining the aerosol performance of the original inhaler. These changes have also led to the Respimat being a reusable device, with the potential for reduced environmental impact.

Aims: The aims of the studies presented here were to evaluate general handling and instructions for use (IFU) of the new reusable Respimat and to compare the reusable inhaler with the marketed disposable device.

Methods: A comprehensive human factors engineering process was carried out: two formative usability studies were conducted to evaluate general handling, IFU and to compare the reusable inhaler with the marketed disposable device. Findings were considered in the design process. The usability confirmatory study of the final inhaler design, carried out in 3 countries, was a human factor study to confirm safe use.

Results: In the first formative study, successful assembly and dose administration were observed for all participants. As removal of the lower casing was evaluated to be difficult, the design was improved to enable easy removal. In addition, changes regarding the dose counter design and IFU were implemented, focusing on cartridge replacement. In the second formative study, the reusable inhaler was compared with the current inhaler and rated to be easier to assemble, particularly regarding removal of the lower part of the case and insertion of the drug cartridge. The new dose- and cartridge-counters, indicating remaining number of actuations and inhaler life span, respectively, were appreciated by participants. The final 3-country usability confirmatory study showed that the reusable inhaler can be used safely and effectively with no harmful use errors.

Conclusion: Implementing human factor engineering in the design process led to the development of a reusable soft mist inhaler with improved usability.