Mass testing system

performanceflowpressure

Overview
The APSD measurement of Dry Powder Inhalers (DPIs) is typically performed under the same conditions as Delivered Dose Uniformity (DDU) testing, with a Preseparator usually interposed between the induction port and stage 0 of a cascade impactor to capture the large, non-inhalable carrier particles and prevent impactor over-loading. For delivered dose DPI testing the test flow rate is set on the basis of a 4 kPa pressure drop across the device to approximate the mean patient inhalation flow rate during clinical use.

APSD impactor options

• Next Generation Impactor (NGI)
• Andersen Cascade Impactor (ACI)
• Multi Stage Liquid Impinger (MSLI)
• Glass Twin Impinger (GTI)

Preseparator (NGI Preseparator) - purpose and features
The Preseparator is placed between the induction port and stage 0 of the impactor to collect large, non-inhalable carrier particles emitted from DPIs, preventing over-loading of the impactor. Typical features and operational notes include:

• High capacity for collection of large mass, non-inhalable powder clouds
• High efficiency two-stage separation
• Sharp and reproducible cut-point between approximately 10-15 microns (dependent on flow rate)

Induction port and P1 measurement
Used with critical flow controllers, an Induction Port P1 Measurement Adapter can be placed between the inhaler and the induction port to measure the P1 pressure drop over the inhaler in the absence of a DUSA for DPIs. This supports setting and confirming the intended pressure-drop-based flow conditions for testing.

System components commonly used in APSD of DPIs

• Mouthpiece Adapter
• NGI Induction Port
• NGI Preseparator
• Next Generation Impactor (NGI)
• Critical Flow Controller (example: TPK 200iX)
• High Capacity Vacuum Pump (example: HCP7)
• Flow Rate Sensor (FRS)
• Inhalytix®+ APSD data analysis software
• NGI cup racks, carrying/washing racks and filter holders

Related testing and automation support
APSD testing of DPIs can be complemented with automation tools and ancillaries to improve throughput and reduce variability. Examples of automation/semi-automation referenced include sample preparation units (SPU 200i), gentle rocker (GR 200i), impactor coater (IC 200i), impactor cleaning systems and other labour-saving devices. These tools reduce handling error, improve reproducibility, and increase testing capacity.

Applications
APSD testing of DPIs is used for delivered dose characterisation, product development, method development, comparative/bioequivalence studies and investigations into variability. Test setups may be adapted to increase clinical relevance by using realistic throat/nasal models and patient breathing profiles.

Technical characteristics / specifications

• Test flow rate basis: set to achieve a 4 kPa pressure drop across the device (to approximate mean patient inhalation flow)
• Preseparator: two-stage separation, high capacity, sharp cut-point ~10-15 µm depending on flow
• Compatible cascade impactors: NGI, ACI, MSLI, GTI
• Induction Port P1 Measurement Adapter: measures pressure drop (P1) over inhaler in absence of DUSA
• Ancillaries commonly used: Critical Flow Controller (e.g. TPK 200iX), Flow Rate Sensor (FRS), High Capacity Vacuum Pump (e.g. HCP7), NGI cooler/tilting platforms, mouthpiece adapters, cup racks
• Data analysis: Inhalytix®+ APSD data analysis software available for APSD processing