Performance testing system BAIs

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Overview
MDI (Metered Dose Inhaler) aerosol characteristics are relatively insensitive to changes in air flow rate because aerosolisation and dispersion mechanisms depend primarily on the force generated by the propellant rather than the patient’s inspiratory effort. For MDI DDU testing the test flow rate is fixed at 28.3 L/min and a vacuum pump is used to draw air through the assembled test set-up at this flow rate. These standard test conditions are not applied when the MDI is intended for use with an add-on device such as a spacer or a valved holding chamber (VHC).

DDU testing with add-on devices and BAIs
When testing Metered Dose Inhalers intended for use with add-on devices (spacers/VHCs) the fixed MDI test flow conditions are not applied. Breath-Actuated Inhalers (BAIs) can be tested using a Breath Actuation Controller (BAC 100i) which initiates flow and simultaneously triggers the breath-actuated inhaler.

Automation & automated DDU testing
The Vertus® III automated shake, fire and shot waste range provides integrated shake/fire/flow control for MDI DDU testing. Key controllable parameters offered by Vertus III systems include:

• The speed, angle and duration of shaking ahead of actuation
• Firing force and the speed of application and release of that force
• The time delay between the end of shaking and device actuation

Automation tools – typical benefits

• Improve efficiency
• Reduce variability
• Eliminate handling errors
• Increase testing capacity

Products / components commonly featured for MDI/BAI DDU systems

• Low Capacity Pump (LCP7)
• Breath Actuation Controller (BAC 100i)
• Inhaler Testing Workstation (ITW)
• Dose Uniformity Sampling Apparatus (DUSA) for MDIs
• Flow Rate Sensor (FRS)
• Flow Meter (DFM 2000)
• Waste Shot Collector (WSC2)
• Mouthpiece / Nosepiece Adapters
• MDI Actuation Sensor
• Temperature / Humidity Sensor

Breath-Actuated MDIs (BAIs)
The Breath Actuation Controller BAC 100i can be used for the testing of Breath-Actuated (or Breath-Operated) MDIs by initiating the flow that simultaneously triggers the breath-actuated inhaler. This enables DDU assessment under conditions that mimic the breath-actuated device behaviour.

Additional notes
DDU testing workflows require collection and drug recovery of individual doses into a collection tube appropriate to the dosage unit sampling apparatus (DUSA) prior to assay. Automated and semi-automated modules (shake, fire, waste collection, flow control and sensors) are used to improve reproducibility and throughput.