DDU of Metered-Dose Inhalers (MDIs)

MDI aerosol characteristics are relatively insensitive to changes in air flow rate because the aerosolisation and dispersion mechanisms are dependent on the force generated by the propellant, rather than the patient’s inspiratory effort. Therefore, for MDIs, the test flow rate is fixed at an arbitrary value of 28.3 L/min. A vacuum pump is used to draw air through the assembled test set-up at this flow rate. However, these test conditions are not applied for DDU testing when the MDI is intended for use with an add-on device such as a spacer or valved holding chamber (VHC).

Lungs Icons

The constant 28.3 L/min air flow rate applied during the testing of MDIs is replaced by a specific patient relevant tidal breath profile more representative of the conditions applied by the patient when using an add-on device.

View Brochure

Related Applications

We also offer a range of equipment for additional MDI testing application support:

Related Services

Training

We offer a range of training courses, presentations and seminars covering a wide range of topics....

Find out More

Servicing

A comprehensive range of both in-house and on-site product servicing options are available...

Find out More

Support

Our team of experienced technicians and engineers are on hand to help and advise ...

Find out More

Related News & Resources