DDU tester SMIs

for aqueous droplet inhalers

Both MDIs and DPIs suffer from the same two inherent problems: low lung deposits (typically 5-20%) and dose variability (often due to patient difficulties in coordination or inspiration). Aqueous Droplet Inhalers (often known as “Solution Metering” or “Soft Mist” Inhalers), are a new generation of inhaler designed to overcome these problems. Since they are active, aqueous-based devices, the DDU testing of ADIs is similar to that of MDIs, with testing carried out at a constant flow rate of 28.3 L/min. DDU Over the Entire Contents In the case of multiple dose devices, tests might need to be carried out throughout the life of the inhaler i.e. dose uniformity over the entire contents.