Filtration

Viral Nanofilter Integrity: Using Variable-Pathlength UV-Vis Spectroscopy for the Gold Nanoparticle Test

Viral filtration (VF) using nanofilters removes endogenous and/or adventitious viruses from biologic drug-substance manufacturing processes (1). The gold particle test (GPT) is performed as part of postuse integrity testing — to complement postuse leakage testing — for cellulose filters such as Planova 20N filters from Asahi Kasei Corporation. First, a proprietary gold-colloid solution matched to the filter type (e.g., 20N) is filtered through the test article. That filter’s pore-size distribution can be assessed using spectrophotometric absorbance readings of the integrity-test…

Addressing Regulatory Requirements for Filter Integrity Testing

Filter integrity is a fundamental element of sterility assurance during production of biopharmaceutical and vaccine products. Integrity test results are a key foundation for drug lot release, so any external element that could affect their reliability must be viewed as a critical issue. But when should a filter integrity test be performed? This article highlights the Sartocheck 5 Plus filter integrity tester as a means to address regulatory requirements. Please fill out the form below to read the full article…

An Integrated Bioprocess for Antibodies: From Harvest to Purified Bulk in Six Hours

Antibody production platform processes have been widely adopted in biomanufacturing, but many unit operations are not suitable for integration and automation. Here we describe the work of integrating unit operations by transforming a column operation to a more robust cassette format. We have selected a biomolecule-friendly buffer (phosphate) to eliminate, or delay, the performance of a circulating tangential flow ultrafiltration/diafiltration (UF/DF) operation, so the harvest-to-purified-bulk process can be integrated, resulting in a single, direct-flow operation, that reduces the batch process…

Making Downstream Processing Continuous and Robust: A Virtual Roundtable

Current biomanufacturing is driven to pursue continuous processing for cost reduction and increased productivity, especially for monoclonal antibody (MAb) production and manufacturing. Although many technologies are now available and have been implemented in biodevelopment, implementation for large-scale production is still in its infancy. In a lively roundtable discussion at the BPI West conference in Santa Clara, CA (11 March 2019), participants touched on a number of important issues still to be resolved and technologies that are still in need of…

eBook: Making Filtration Work

Steady improvements in batch-fed cell culture have led to bottlenecks in downstream processing. Filter suppliers are working to improve available tools for purifying therapeutic proteins, to wring every possible efficiency out of those tools, and to make them operate together harmoniously. The combination of high titers and high-value products places a premium on preventing yield loss. Bioprocessors want to optimize filtration primarily for cost reasons. In this eBook, author Angelo DePalma discusses financial aspects, clarification/harvest and virus filtration options, and…

A UF–DF Screening System for Bioprocess Development: Efficient and Cost-Effective Process Fit and Scale-Up to Manufacturing

Ultrafiltration and diafiltration (UF–DF) of therapeutic proteins are performed in either tangential or crossflow mode using membrane filters. UF–DF plays a critical role in both downstream and upstream processes for the biopharmaceutical industry (1). In upstream production processes, classical tangential-flow filtration (TFF) or alternating tangential-flow (ATF) systems are used in high–cell-density perfusion for protein expression by cell culture (2). TFF is used in downstream processing for UF–DF and concentration of therapeutic proteins. TFF unit operations are common in protein purification…

Filter-Based Clarification of Viral Vaccines and Vectors

Viral vaccines rely on the antigen properties of a virus or virus-like entity to trigger an immune response and induce immune protection against a forthcoming viral infection. Through development of recombinant viral vaccines, developers can reduce risks associated with the presence of live and inactivated viruses. Instead, recombinant vaccines induce immunity against a pathogen by relying on the capacity of one or more antigens delivered by means of viral vectors or the baculovirus/plasmid system (1). Viral vaccines are formulated with…

IgG Purification By Ultrafiltration: Time for Another Look

One of the early disappointments in development of immunoglobulin G (IgG) purification technology was ultrafiltration on membranes with 50–100 kDa cutoffs. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed that most host cell proteins were smaller than that. IgG was retained. Parallel concentration and buffer exchange could be performed going into a follow-on polishing step. These features made it an obvious candidate for initial capture, but it did not perform as hoped. Membrane fouling sabotaged its concentration–diafiltration potential, and prohibitive…

Advanced Viral Clearance Study Design: A Total Viral Challenge Approach to Virus Filtration

Biologics derived from mammalian organisms have been accepted for therapeutic use for almost a century (1). However, these pharmaceuticals have the potential for contamination with pathogenic adventitious agents such as viruses. With cell-line–derived recombinant proteins, the viral risks commonly include viruses in the Retroviridae and Parvoviridae families (2). As patient safety and manufacturing facility suitability became significant concerns in the 1980s and 1990s, several industry and regulatory bodies reached consensus on how to approach the unique challenges of viral safety…

Evaluating Adsorptive Filtration As a Unit Operation for Virus Removal

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…