Filtration

Artifacts of Virus Filter Validation

Virus filters are used in biomanufacturing to ensure the safety of biopharmaceutical drug products. As part of filter implementation, manufacturers are required to validate that the filtration process can indeed remove virus. Validations are typically performed at contract testing organizations (CTOs) that are “equipped for virological work and performed by staff with virological expertise in conjunction with production personnel involved in designing and preparing a scaled-down version of the purification process” (1). Virus removal capability of a filtration process is…

Downstream Technology Landscape for Large-Scale Therapeutic Cell Processing

The cell therapy industry (CTI) is poised to grow rapidly over the next decade, treating millions of patients and generating annual revenues into the tens of billions of US dollars (1, 2). To meet that high-growth demand, large CTI system manufacturers (e.g., Corning, Nunc/Nalgene, and GE Healthcare) and leading contract manufacturing organizations (CMOs, such as Lonza) are developing and integrating new upstream technology platforms such as gas-permeable membranes and microcarrier-based bioreactors to significantly increase therapeutic cell culture productivity. As those…

Advocating an Evolution

In a 2006 report, the US Department of Health and Human Services hailed regenerative medicine as “the vanguard of 21st century healthcare” and “the first truly interdisciplinary field that utilizes and brings together nearly every field in science” (1). To fuel support for regulatory, legislative, and reimbursement initiatives in this new therapeutic class, a small group of scientists, life science business executives, patient advocates, and other experts formed the Alliance for Regenerative Medicine (ARM, http://alliancerm.org). Starting with 17 charter members,…

Performance of a Salt-Tolerant Membrane Adsorber in Flow-Through Mode

Monoclonal antibodies (MAbs) have become the most prevalent therapeutics in the biopharmaceutical industry. Their downstream purification typically involves protein A chromatography as a capture step followed by one or two additional chromatographic polishing steps. Additional unit operations dedicated specifically for viral clearance (e.g., viral inactivation and filtration) are added to ensure product safety. According to a survey of Amgen processes, after processing through a protein A column, only trace amounts of impurities such as Chinese hamster ovary cell protein (CHOP)…

Integrity Testing of Ultrafiltration Systems for Biopharmaceutical Applications

    Ultrafiltration (UF) is a membrane-based separation technology commonly used in the biopharmaceutical industry for concentration or diafiltration of protein solutions to remove low–molecular-weight (LMW) impurities or exchange buffers. The nominal MW limit of UF membranes ranges from 1,000 Da (1 kDa) to 1,000,000 Da (1,000 kDa). A target product is retained by the membrane while lower-MW solutes or impurities pass through (1). For a target product with a smaller MW than the impurities, separation is accomplished by allowing…

Sterilizing-Grade Filter Sizing Based on Permeability

    Sterilizing filtration renders biotherapeutics free of biocontamination. In many cases, sterilizing-grade filters also reduce bioburden or facilitate closed or aseptic processing. They are used to filter active pharmaceutical ingredients (APIs), formulated bulk, cell culture media, buffer, additives, process intermediates, and so on. Such applications are often critical for ensuring a successful batch operations. Nonetheless, a significant amount of time and resources are typically not devoted to establishing filter sizing requirements for “simple” applications such as buffer filtration. Here,…

A Decade of Filtration

    Filtration is just as vital to bioprocessing as chromatography — and arguably even more so. Filters are not only used as downstream unit operations in themselves, but also in support of nearly every other step in bioprocessing. Gas or liquid filters ensure the quality of incoming air and feeds for cell culture operations, clean the circulating media in perfusion processes, aid in harvest clarification, and remove buffers from chromatographic eluate after chromatography columns. They are used in formulation…

Large-Scale, Single-Use Depth Filtration Systems

    Clarifying cell culture broth is the first downstream unit operation in an elaborate sequence of steps required to purify a biological therapeutic. A combination of centrifugation, depth filtration, or tangential-flow filtration (TFF) is used for that operation. The availability of largescale, single-use, depth filtration technology in the recent years, however, has given process developers the capability to improve and simplify downstream processes.   Clarification of Cell Culture Streams   The main purpose of clarification is to efficiently separate…

Integrity Testing of Sterilizing-Grade Filters

    Integrity testing of sterilizing-grade filters is necessary to reliably prevent damage to these sterile barriers from compromising the production of biopharmaceuticals. Documented integrity test results are essential to a manufacturing audit trail for releasing pharmaceutical products (1, 2). Accordingly, problems encountered during this testing can lead to considerable financial damages and substantial delays or even entirely prevent a production lot from being released to the market. Therefore, filter integrity testing is a critical step with high economic importance…

Retention of Highly Penetrative A. laidlawii Mycoplasma Cells

    Mycoplasma are infamous for contaminating cell culture lines at rates as high as 80% (1,2,3,4,5). For biopharmaceutical processes, the inadvertent use of contaminated culture medium or medium components can lead to contamination of an aseptic process-validation media fill or cell culture medium for a bioreactor (6,7,8,9,10,11). Thoroughly testing medium components before use is generally impractical because of the large volume of material in use. Frequently, culture media cannot be autoclaved (because of the presence of heat-sensitive components or…