eShop
Sign in
English
This article aims to present the virus retention performance of Cobetter Viruclear™ RC filters under high pressure, low pressure, normal filtration pressure, and interruption/pause conditions.
Case Study 1:
Using RC H syringe filter (catalog number: VFHRCDSN1P) to evaluate the removal of PPV under high-pressure and low-pressure conditions, with process interruptions and repeated pressure cycles applied as worst-case scenarios.
The feed material was a 50 g/L IVIG solution, and the upstream spike level of PPV was 8.0 log PFU.
The PPV titers in the feed and filtrate were determined using a plaque assay, and the viral removal efficiency was expressed as the Log Reduction Value (LRV).
Note: The low pressure was set at 15 psi and the high pressure at 50 psi. The target filtration load was 160 L/m². When the load reached 80 L/m², the pressure was released, followed by a 30-minute process pause, and then filtration was resumed at the previous pressure. When the load reached 120 L/m², a single step of 10 pressure cycling operations was performed, with 30-second cycles alternating the filtration pressure between 0–15 psi (low pressure) or 0–50 psi (high pressure), before continuing to the target load. A long 12-hour pressure pause was then applied, followed by a 30 L/m² buffer flush.
Experimental Conclusion:
The LRV results determined by plaque assay showed that under both high-pressure and low-pressure conditions, PPV levels were reduced below the quantitation limit, demonstrating the filter’s robust viral removal performance under both pressure conditions.
Case Study 2:
Using RC H syringe filter (catalog number: VFHRCDSN1P) to evaluate the removal of MVM under high-pressure and low-pressure conditions, with process interruptions and repeated pressure cycles applied as worst-case scenarios.
The feed material was a 10 g/L mAb1 solution, and the upstream spike level of MVM was 8.0 log PFU.
The MVM titers in the feed and filtrate were determined using a plaque assay, and the viral removal efficiency was expressed as the Log Reduction Value (LRV).
Note: The low pressure was set at 15 psi and the high pressure at 50 psi. The target filtration load was 320 L/m². When the load reached 80 L/m², the pressure was released, followed by a 10-hour process pause, and then filtration was resumed at the previous pressure. When the load reached 200 L/m², a single step of 10 pressure cycling operations was performed, with 30-second cycles alternating the filtration pressure between 0–15 psi (low pressure) or 0–50 psi (high pressure), before continuing to the target load. A long 30-minute pressure pause was then applied, followed by a 30 L/m² buffer flush.
Experimental Conclusion:
The LRV results determined by the plaque assay showed that under both high- and low-pressure conditions, the detected MVM levels were reduced to below the limit of quantification, demonstrating the robust virus removal capability of the filter under both pressure conditions.
In summary
Under different pressure conditions, Cobetter Viruclear™ VF series virus filters demonstrate robust retention capability for parvoviruses. Virus clearance validation studies are scale-down models that simulate the operational parameters of actual large-scale manufacturing processes, with the focus on evaluating the virus removal performance of the filter under real production parameters.
Considering the core principles of relevant domestic and international regulations or guidance documents—namely, verifying the virus clearance capability of the actual manufacturing process—we recommend the following:
1. The production process standard operating procedure (SOP) should define a stable and controllable operating pressure range for the manufacturing process.
2. A scale-down model that is representative of the actual manufacturing process should be established.
3. For virus clearance (VC) validation, it is generally recommended to use the controlled operating pressure used in actual production. When designing the VC validation study, the filtration pressure should be set to the upper pressure limit defined in the SOP, and at least one pressure interruption (reduced to 0 psi) should be introduced and maintained for a certain period to evaluate the impact of extreme low-pressure conditions. Typically, the interruption is performed at least once before the buffer flush, when the protein load and viral load are at their maximum, representing a combined worst-case scenario. Successful validation under this condition can also provide additional operational flexibility for handling unexpected situations during manufacturing.
4. If conditions permit, it is recommended to conduct an additional study evaluating the virus retention capability for MVM or PPV under the lower pressure limit specified in the SOP.
