The impact of possible improper use on the performance in vitro of NEXThaler in comparison with Ellipta inhaler

The correct use of dry powder inhalers by the patients is essential to ensure effective treatment and management of the disease. The purpose of the work was to assess the consequence of inhaler misuse in terms of emitted dose and aerodynamic parameters. One reservoir multidose device (Foster-NEXThaler®) and one pre-dosed device (Relvar-Ellipta®), both sharing the "open, inhale and close" procedure, were the subject of the study. NEXThaler activated at different degrees of inclination showed a consistent dose delivery for both the drugs included in the formulation (beclometasone dipropionate/formoterol fumarate). Contrary, Ellipta showed a decrease of the emitted dose for both fluticasone furoate (FluF) and vilanterol trifenatate (VT) when the device was operated facing downward (-14% at 45° and -22% at 90°). Similarly, the delivered dose of NEXThaler was unaffected by an accidental fall, while Ellipta released FluF and VT doses 50% lower than control values. The presence of the dose protector in NEXThaler offers the advantage of retaining the powder if the inhaler is subjected to incorrect manipulations. Both products proved to be reliable in double activation. Finally, simulation exhalation conditions impaired, although not significantly, the aerodynamic profile of the two products.