DDU of Nebulisers

The delivered dose testing of nebulisers is carried out to determine the total amount of drug a patient might be expected to receive during a treatment period, rather than through one inhalation. Given the mode of operation of nebulisers, well-defined tidal breathing profiles for specific patient types are specified for testing. The two tests specified in the Pharmacopoeias to characterise delivered dose, Active Substance Delivery Rate and Total Active Substance Delivered, are based on tidal flow conditions generated by a breathing simulator, as opposed to fixed flow rates.