In vitrocomparison of dose accuracy of two budesonide/formoterol dry powder inhalers

Background: To obtain the desired clinical effect consistently it is essential that dry powder inhalers (DPIs) perform reliably. Aim: To compare in vitro dose accuracy of two budesonide/formoterol fumarate dihydrate (formoterol) 160/4.5 µg per inhalation DPIs, Bufomix Easyhaler ® (Orion, Finland) and Symbicort ® Turbuhaler ® (AstraZeneca, UK). Method: Dose deliveries were measured using flow rates achievable by the target patient population, asthmatic and COPD patients. The minimum (10 th ), median (50 th ) and maximum (90 th percentile) flow rates were applied as instructed in the guidance (CPMP/EWP/4151/00 Rev1). 36 inhalers representing 2 batches of both products were measured. 10 doses were analysed: 3 from the beginning, 4 from the middle and 3 from the end of labelled number of doses. Results: The dose accuracy of the inhalers for budesonide and formoterol are illustrated in the Figure 1. The differences in dose accuracy at the three different flow rates were statistically significant. The variability of delivered dose from Easyhaler is statistically significantly smaller than from Turbuhaler (p Figure 1. Budesonide and formoterol delivered dose results from 160/4.5µg per inhalation Bufomix Easyhaler® and Symbicort® Turbuhaler® DPIs applying air flows of 10 th , 50 th and 90 th percentiles target patient populations. Conclusion: The Bufomix Easyhaler® dose accuracy is significantly better than Symbicort® Turbuhaler®.