RPRD | Development of an Automated Filter Integrity Test Device Using a Back…

Development of an Automated Filter Integrity Test Device Using a Back Pressure come from Bulk Flow and Its Application 

Chang-Sik Yoon, Yong-Hyun Cho, Tae-Sik Jeong², Hee-Won Park,  Yong-Seok Lee, Jae-Hyung Lee, Hong-Jae Lee, Jin-Eui Kim,  Yun-Sang Lee, Keon-Wook Kang, Jae Min Jeong*  PET center, Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea  ²Department of Bio Medical Engineering, Seoul National University Hospital, Seoul, Korea 

Purpose 

Filter integrity test is mandatory under the CGMP regulation. For this, we performed bubble point tests using analog pressure gauges. However, this method has several problems: subjective interpretation, difficulty to calibration, and unclear difference between diffusion and bulk flow. In order to solve the problems, we developed an automated device capable of reading digital values for the filter integrity. 

Materials and Methods 

After connection of a filter to the device, nitrogen gas was supplied to a filter inlet through 2-way valve (Figure. 1). Two needle valves were used to open the nitrogen to pressurize the membrane in filter. As the inlet pressure increased, 2nd digital indicator value also increased slowly by diffusion flow which was generated from filter outlet. As soon as an inlet pressure reached to bubble point, the flow rate increased suddenly. And then the 2-way valve was closed to hold the pressure of filter inlet. The held pressure was displayed on 1st digital indicator which demonstrated bubble point test result. We tested six different sterile filters, such as AEF1NTE, Millex-GS, Millex-FG, CathivexGV, SFCA, and Millex-HV, using this device. 

Results 

The time per test was 10±1 sec. Bubble point pressures for AEF1NTE, Millex-GS, Millex-FG, Cathivex-GV, SFCA, and Millex-HV were 60.3±0.5 psi, 60.5±0.3 psi, 22.8±0.1 psi, 62.7±0.5 psi, 63.7±0.3 psi, and 31.2±0.1 psi, respectively. 

Conclusion 

We developed an automatic device for the filter integrity test, which enabled us to obtain reproducible bubble point results and to reduce test time significantly.