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High resolution removal of virus from protein solutions using a membrane of unique structure
A J DiLeo1, A E Allegrezza, S E Builder
1Millipore Corporation, Bedford, MA 01730.
Abstract:
We describe a new class of membrane that has the capability of removing particles such as viruses from solution with resolution and reproducibility superior to that of conventional membranes. This composite membrane is composed of a pre-formed microporous membrane plus a thin asymmetric, finely porous retentive layer that is quite different from conventional ultrafilters. The protein sieving characteristics of this membrane are nearly equivalent to, but slightly less than, that of conventional 100,000 Dalton cut-off ultrafiltration membranes. This membrane uniquely shows particle retention characteristics that increase monotonically from 3 to 8 logs as a function of particle diameter in the range of 28 to 93 nm. The performance of this membrane in both a single stage and a two stage system show that 4 to 6 log overall removal of virus particles in the size range 30 to 70 nm is possible with simultaneous high recovery of product protein. Clearance factors exceeding 6 logs are possible with viruses larger than 78 nm. In addition, the performance of process systems containing this membrane is predictable in accordance with the general membrane properties and equilibrium mass balance models. This membrane system is fully validatable and can be used in conjunction with other validated operations in a down-stream process to reliably achieve an over-all reduction of 12 logs of known or putative virus particles.
Insights
A novel composite membrane effectively removes viruses from solutions with superior resolution and reproducibility. This validated system achieves a 12-log reduction of virus particles, ensuring high product protein recovery.
Area of Science:
- Biotechnology
- Materials Science
- Chemical Engineering
Background:
- Conventional membranes face limitations in particle and virus removal efficiency.
- There is a need for advanced filtration technologies in biopharmaceutical processing.
Purpose of the Study:
- To introduce and characterize a new composite membrane for superior particle and virus removal.
- To evaluate the performance of this membrane in single-stage and two-stage systems.
- To demonstrate the predictability and validity of the membrane system for downstream processing.
Main Methods:
- Fabrication of a composite membrane with a microporous support and a finely porous retentive layer.
- Characterization of protein sieving and particle retention properties.
- Performance evaluation in single-stage and two-stage filtration systems.
- Validation of the system using equilibrium mass balance models.
Main Results:
- The composite membrane exhibits particle retention increasing from 3 to 8 logs for particle diameters of 28 to 93 nm.
- Achieved 4 to 6 log overall removal of virus particles (30-70 nm) with high protein recovery.
- Demonstrated clearance factors exceeding 6 logs for viruses larger than 78 nm.
- System performance is predictable and the membrane is fully validatable.
Conclusions:
- The novel composite membrane offers enhanced virus removal capabilities compared to conventional membranes.
- The validated membrane system can achieve a reliable 12-log reduction of virus particles in downstream processing.
- This technology holds significant potential for biopharmaceutical purification and safety.