The aim of this study was to analyse the effect of breathing parameters, age, gender and disease status on the lung doses of the two ICS + LABA fixed combination dry powder drugs. Breathing parameters of 113 COPD patients were measured while inhaling through emptied NEXThaler® and Ellipta® inhalers and the corresponding lung doses were calculated. Lung dose of Foster® NEXThaler® was superior to the lung dose of Relvar® Ellipta® in around 85 % of the patients. The average value of the ratio of bronchiolar to bronchial deposition fractions was 5.0 for Foster® NEXThaler® and 2.6 for Relvar® Ellipta®. Lung dose was sensitive to the inhalation parameters, such as peak inhalation flow, inhaled volume and breath-hold time. For both studied drugs the dose to the lungs was relatively high for moderate PIF values, but it declined for low (<35 L/min) and high (>95 L/min) PIFs. The lung dose increased by the increase of the inhaled volume, but saturated over 1.0 L of inhaled air. Longer breath-hold time led to higher lung deposition, but the dependence was drug-specific. FEV1 (%) and FEV1/FVC (%) did not influence the lung dose significantly (p = 0.05). Exacerbating patients had lower lung doses (28.8 ± 5.8 % for Foster® NEXThaler® and 23.7 ± 3.8 % for Relvar® Ellipta®) than their non-exacerbating counterparts (33.7 ± 6.1 % for Foster® NEXThaler® and for 24.9 ± 3.9 % for Relvar® Ellipta®). The exact clinical consequences of the differences between the deposition distributions of the two drugs could be assessed only by systematic clinical trials.
Keywords: Airway deposition; COPD management; Numerical simulation; dry powder aerosol drug.
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