In most downstream purification processes designed for biopharmaceutical drug production, dilution and diafiltration sequences are unavoidable. Such operations are routinely used to adjust a feedstock or chromatographic fraction to the optimal conditions required for best process performances. Nevertheless, those steps are often time, water, and labor consuming without participating directly in final product purification. Because biopharmaceutical production is increasingly driven by cost reduction, a possible means for enhancing process economics is to streamline purification by eliminating these unit operations before…
Chromatography
Purifying Common Light-Chain Bispecific Antibodies
A bispecific antibody can bind two different antigens. Immunoglobulin G (IgG) type antibodies have two binding sites with different variable regions. An IgG variable region is made up of a variable light-chain sequence (VL) and a variable heavy-chain sequence (VH). The light chains (LCs) of common LC antibodies are identical for both variable regions, leaving the heavy chain (HC) for generating different specificities. Thus, recombinant host cells for production of common LC bispecific antibodies carry genes for both HCs, with…
A Decade of Harvesting Methods
The preliminary separation of a protein of interest from a reactor “soup” of process impurities (e.g., cell debris, colloids, lipids) is the first step in a downstream process. It is also a primary step that introduces a significant risk of product degradation, bioburden concerns, or process errors, especially if a harvest method is not a good “fit” with a newly designed bioreactor (e.g., single-use) or fermentation vessel. In 2003, BPI’s first year, industry concerns revolved around potential capacity…
A Decade of Chromatography: A Powerful Technology Reasserts Itself
Chromatographic separations are vital both to the analysis of biological macromolecules and to their manufacturing. When properly applied, chromatography provides exquisite specificity in separating different molecules from solution based on their size, electrical charge, or other physicochemical properties. Large liquid chromatographic (LC) columns remove host-cell nucleic acids, endotoxins, viruses, and process intermediates from harvest material. Combine high-pressure liquid chromatography (HPLC) with mass spectrometric (MS) or ultraviolet–visible (UV–vis) spectroscopic detection, and you can qualify and quantify macromolecules in such…
Approaches to Debottlenecking and Process Optimization
Two major challenges associated with optimizing biomanufacturing operations remain unresolved. The first is variability: how to understand and improve manufacturing with significant variation in process times throughout all unit operations. The second is complexity: modern biomanufacturing facilities are complex and interconnected, with piping segments, transfer panels, and valve arrays, as well as water for injection (WFI) and other shared resource constraints. That complexity is becoming even greater with the need for process standardization and processing of higher (and…
Key Downstream Problems Decline While Industry Continues to Demand New Technologies
Downstream problems for biomanufacturers finally appear to be lessening. Over the past six years, demand for better purification has topped the list of biomanufacturing areas in need of improvement. This year, however, it appears that purification woes — though still a hot topic — are cooling off. After seven years of measuring the impact on capacity of specific biomanufacturing operations, preliminary data from BioPlan Associates’ ninth annual survey shows that activities associated with both optimizing internal downstream processes (DSPs) and…
Revisiting Protein A Chromatography
Due to the molecular complexity of monoclonal antibodies (MAbs) and potential impurities in cell culture media before purification (host-cell proteins, DNA, media components) (1), subsequent downstream operations must consistently and reproducibly purify products to ensure safety and efficacy. The latest member of GE Healthcare’s MabSelect family is called MabSelect SuRe LX (2). As Table 1 shows, it has been developed using the same highly cross-linked agarose base matrix and protein A ligand as for other MAb affinity resins (Table 1).…
Understanding Chromatographic Media Ligand Density
The concept of quality by design (QbD), although not new, has presented implementation opportunities and challenges to both the bioprocessing industry and regulators (1,2,3,4). Tools such as design of experiments (DoE), cause and effect analysis, and multivariate analysis provide for systematic risk assessment and help identify critical quality attributes (CQAs) and critical process parameters (5,6,7). QbD is intended to ensure that manufacturing processes make products that meet predefined quality parameters. Key elements in defining such parameters (quality profile)…
Efficient Aggregate Removal from Impure Pharmaceutical Active Antibodies
Polishing with membrane chromatography (MC) has achieved acceptance as state-of- the-art technology for charged impurities. Traditionally, anion-exchange (AEX) and cation-exchange (CEX) membrane chromatography have been used to remove charged contaminants such as host-cell proteins (HCPs), recombinant DNA, protein A, endotoxins, and viruses. In monoclonal antibody (MAb) processes, polishing steps usually follow a protein A affinity column step. In some cases, CEX capture is applied, either with at least one AEX or a combined AEX and CEX step. The latter may…
Industrial-Scale Biochromatography Columns Address Challenging Purification Needs
Chromatographic purification remains the most critical step in biopharmaceutical downstream processing. Its purpose is to separate biologic impurities such as host-cell proteins (HCPs), nucleic acids, and oligomers from a target biologic, which must be purified to very high levels (often >99%). Biological separations usually require medium to high salt concentrations and bear inherent risks of microbial contamination in waterbased process streams. Thus they require specifically designed equipment. Depending on process constraints, chromatographic media, and equipment limitations, biochromatographic separations…