Filtration

Evaluating Adsorptive Filtration As a Unit Operation for Virus Removal

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Most recombinant monoclonal antibodies (MAbs) are produced by mammalian cells. Because biopharmaceuticals derived from mammalian tissue culture carry the risk of adventitious virus contamination, regulatory agencies expect risk-mitigation strategies to include validation of purification unit operations for their ability to clear viruses (1). Guidelines from the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) describe how to prove viral clearance in downstream purification processes using an orthogonal approach (2). Viral log10 reduction values (LRVs) are…

March 23, 2018

eBook: Development of a Representative Scale-Down UF/DF Model: Overcoming Equipment Limitations and Associated Process Challenges

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Scale-down models (SDM) are physical, small-scale models of commercial-scale unit operations or processes that are used throughout the biopharmaceutical industry for validation studies, commercial deviation investigations, and postapproval process improvements. To support these studies, regulatory guidelines state that SDMs should be representative of the commercial process. For some downstream unit operations such as column chromatography, developing a representative SDM is straightforward because a linear scale-down approach can be used. However, developing a representative SDM for other downstream unit operations such…

February 27, 2018

New Dimensions in Single-Use Filtration

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Whether viral vectors are clarified or the bioburden after cell harvest needs to be reduced to recover antibodies, such applications in biopharmaceutical production require large filtration areas. Single-use technologies are indispensable in many such bioprocesses. Although some single-use filter assemblies have reached their limits, Sartorius Stedim Biotech has made developments to revolutionize these production steps. Scale-Up Limitations in Single-Use technology Conventional stainless steel process systems have been established for decades in the pharmaceutical industry. They are the basis of safe…

February 14, 2018

Scaling Considerations to Maximize the High-Area Advantage

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Maximizing filtration-area density is a design strategy to minimize filter footprint and improve filtration process economics. Pleated membrane formats commonly are used to achieve that goal for sterilizing-grade filters operating in dead-end mode (also known as normal-flow filtration). Although high-density pleat geometries increase productivity for a device, such formats can present unique challenges. One of the most common concerns is that pleat formats can introduce flow resistance that impedes a device’s filtration efficiency, particularly for high–pleat-density geometries (1, 2). Filtration…

May 18, 2017

Examining Single-Use Harvest Clarification Options: A Case Study Comparing Depth-Filter Turbidities and Recoveries

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Steadily increasing demand for biopharmaceutical drugs has led the industry to examine its manufacturing scales while pressuring research and development groups to produce high-yielding clones and processes. Improved media, feed supplements, bioreactor designs, and control of process parameters have helped biomanufacturers achieve multifold increases in volumetric productivity from production bioreactors. However, cell culture processes are significantly affected by their bioreactor’s ability to support cells at higher densities and sustain cultures at lower viabilities. With the implementation of a number of…

February 13, 2017

Downstream Disposables: The Latest Single-Use Solutions for Downstream Processing

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Downstream processing has been considered a “bottleneck†in the manufacture of protein biotherapeutics ever since cell culture engineers began dramatically improving production efficiencies around the turn of the century. And as single-use technologies have grown in importance and acceptance, offering more solutions every year, their biggest challenges too have been in the separation, purification, and processing that follows product expression in cell culture. Many of the technologies familiar to process engineers — e.g., centrifugation and chromatography — present technical and…

January 20, 2017

Single-Use Depth Filters: Application in Clarifying Industrial Cell Cultures

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For current process development phases, many biomanufacturers’ attention is directed increasingly to the first unit operation in downstream processing, which is the removal of cells and cell debris from culture broth and clarification of supernatant containing a biopharmaceutical product. Given the high cell densities achievable with both mammalian and microbial cell culture processes, primary recovery can be a significant challenge. The current trend in cell culture is to increase product titers with enriched culture media, improved cell productivity, and increased…

January 20, 2017

Membrane Adsorbers, Columns: Single-Use Alternatives to Resin Chromatography

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Filtration membranes are used extensively throughout the biopharmaceutical industry for a range of applications, from coarse filtration to nanofiltration. Advantages of filter technologies include easy scaling, disposability, and (for many membrane filters) rapid and robust performance in a single-pass. The same advantages have been realized with membrane adsorbers. Chromatography resins are inherently disadvantaged by diffusion limits of the pores in chromatography media. Therefore, resin columns must be significantly oversized to match the performance of high productivity bioreactors. By comparison, membrane…

January 20, 2017

Membrane-Based Clarification of Polysaccharide Vaccines

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Polysaccharide vaccines are essential for protection against infectious diseases, which remain an alarming cause of mortality. The first glycoconjugate vaccine for use in humans — a Haemophilus influenzae type b (Hib) conjugate — was licensed in the United States in 1987. This vaccine successfully reduced the incidence of invasive Hib disease in childhood and led to the further development of conjugate vaccines designed to prevent infection by other encapsulated bacteria (1). Polysaccharides are relatively complex carbohydrates made up of many…

November 17, 2016

Best Practices for Critical Sterile Filter Operation: A Case Study

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A number of regulatory guidelines recommend preuse integrity testing of critical sterilizing liquid filters for aseptic processing (1–3). Before sterilization, a preuse test will confirm that a filter is installed properly and was not damaged during shipment or handling. Performing a preuse test after sterilization detects damage that may have occurred during the sterilization cycle. Testing after sterilization limits risk, so it is a practice applied based on risk assessment. Because it is perceived to reduce business loss risk, preuse…

May 11, 2016