New Flow Controller for Dry Powder Inhaler Testing

The new Critical Flow Controller TPK 2000 from Copley Scientific Ltd is designed to control and document all the critical parameters associated with dose uniformity and cascade impactor testing for dry powder inhalers (DPIs). Based on the company's original TPK critical flow controller, now widely recognised as an industry standard, it offers significantly enhanced functionality including an RS232 interface, menu driven operation and environmental condition measurement.

The US and European Pharmacopoeias (USP and Ph. Eur) specify that flow rate, total air volume and flow stability must be carefully controlled during DPI testing. Flow rate must be manipulated to generate a 4 kPa pressure drop across the DPI, up to a maximum flow of 100 L/min, with the duration of flow controlled to give a total air volume of 2 or 4 L. Critical flow across the flow control valve is also required to minimise flow rate instability.

The TPK 2000 makes test set-up easy in line with these specifications. A user-friendly interface provides guidance through the testing procedures specified by the pharmacopoeias. Following an initial set-up procedure, which identifies the air flow rate required for testing based on the flow resistance of the device, the TPK 2000 automatically measures and/or calculates all required variables including,test flow rate and ambient conditions - air pressure, temperature and relative humidity as well as monitoring critical flow. These parameters along with system calibration data can be printed or exported via RS232 (or USB). An optional interface with Copley's flow meter model DFM 2000 permits volumetric air flow rate measurement during the set-up routine, simplifying and accelerating this part of the procedure.

Utilizing two external pressure taps the TPK 2000 can also be used to determine leak rates and total pressure drops for both Next Generation and Andersen Cascade Impactors; valuable data for monitoring day-to-day impactor performance and suitability. The TPK 2000 is designed for user calibration within the lab environment.