Effect of breath-actuated mechanism on the emitted particle characteristics and lung deposition of a fixed combination drug

Introduction: The breath-actuated mechanism (BAM) is a mechanical unit included in NEXThaler® with the role of delaying the emission of the drug until the inhalation flow rate of the patient is sufficiently high to detach the drug particles from their carriers. Objective: The main objective of this study was to analyse the effect of the presence of BAM on the size distribution of the emitted drug and its airway deposition efficiency and distribution. Methods: Size distributions of Foster® NEXThaler® drug particles emitted by dry powder inhalers (DPI) with and without BAM have been measured by a Next Generation Impactor (NGI). p50 inhalation profile of asthmatic patients was used for both experimental and modelling purposes. Upper airway and lung deposition fractions were computed assuming 10 s breath-hold time. Results: The number of emitted fine and extrafine particles increased by the inclusion of BAM (Figure 1). Fine particle fraction (FPF) of the steroid component increased from 26.7% to 49.3%. Upper airway dose expressed as a percent of the nominal emitted dose decreased from 74% to 51%, while lung dose increased from 25.5% to 40% due to BAM. Figure 1. Cumulative size distribution Conclusion: The Chiesi NEXThaler® BAM mechanism is a unique feature enabling enhanced drug delivery to the lungs.