Chromatography

Hydrophobic-Interaction Membrane Chromatography for Large-Scale Purification of Biopharmaceuticals

    Biopharmaceutical manufacturing is divided into two areas: upstream fermentation or cell culture and downstream purification processes. Each area contains multiple unit operations. A unit operation is defined as a step in processing using a particular type of equipment. Here, we focus on downstream process development, which must reliably produce a highly purified drug substance (often >99%). Downstream processing includes recovery, capturing, and polishing steps. The primary downstream unit operation is chromatography because of its simplicity and high resolving…

Development of a High-Capacity MAb Capture Step Based on Cation-Exchange Chromatography

Protein A affinity chromatography is traditionally used as the capture step for monoclonal antibodies (MAbs) (1,2,3). It yields high purity because only the fragment-crystallizable (Fc) region of an antibody (IgG1 or IgG2) or Fc-containing fusion protein can bind to the protein A ligand. The resulting specificity provides substantial reduction in impurities such as host cell proteins (HCPs) and DNA (4,5,6,7,8). The dynamic binding capacity of protein A chromatography resins is generally ≤40 g/L and depends highly on residence time because…

Increasing MAb Capture Productivity

Continually increasing bioreactor titers is placing pressure on downstream processing, especially chromatography steps, to process the greater mass of protein produced. Whereas an order of magnitude increase has been seen in titers over the last few years, no similar increase has yet been achieved in the capacity of chromatography resins. Meanwhile, the industry is coming under rising pressure to reduce manufacturing costs and the resulting cost per gram of monoclonal antibodies (MAbs) produced. Because of the specificity it offers, protein…

MAb Contaminant Removal with a Multimodal Anion Exchanger

Monoclonal antibodies (MAbs) constitute ∼30% of the biopharmaceutical products currently under development (1). An increasing demand for MAbs during the past decade has led to intense development of high-expression cell cultures (2). Today, it is possible to see titers of 4–5 g/L, and expression levels as high as 15 g/L and greater have been reported. As a consequence, demand has increased for more efficient downstream processes. That demand, combined with its potential for reducing time-to-market, has increased interest in the…

Rapid Purification of Lys-C from Cultures

Endoproteases specific for cleavage of peptidyl bonds on the C-terminal side of lysine residues (e.g., Lys-C) are produced from a number of bacterial species, including Achromobacter lyticus (1), Pseudomonas aeruginosa (2), and Lysobacter enzymogenes (3). The Achromobacter protease 1 (API) protein has been substantially characterized (4,5,6) and shown to be a resilient enzyme that can specifically cleave after lysine residues under a wide range of buffer conditions, including high concentrations of denaturing agents such as urea and sodium dodecyl sulphate…

Purifying a Recalcitrant Therapeutic Recombinant Protein with a Mixed-Mode Chromatography Sorbent

Mixed-mode chromatography sorbents can save time and money by reducing the number of steps required to purify recombinant proteins. They also have the potential to purify proteins that single-mode sorbents cannot. As the term mixed mode suggests, these sorbents contain ligands that offer multiple modes of interaction. Although mixed-mode sorbents are used extensively in solid-phase extraction for high-pressure liquid chromatography (HPLC) sample preparation — and to a more limited extent in analytical HPLC — these resins are generally unsuitable for…

Quantifying Trends Toward Alternatives to Protein A

Problems associated with affinity purification in antibody production continue to increase as upstream cell culture expression levels improve. As a result, many vendors and users in the biopharmaceutical industry are working to identify alternative technologies that can replace tried-and-true column chromatography. In the fifth annual report and survey by BioPlan Associates, 434 global respondents pointed to bottlenecks created by downstream processes as one of their most serious manufacturing problems today (1). Amost two-thirds (63.8%) said their facility is experiencing some…

How to Improve Your Implementation of Two-Dimensional Preparative HPLC

The biologics and natural product industries rely heavily on separation technology. Sample analyses are undertaken on the analytical scale, and isolation and purification are undertaken at the preparative scale. Key target components are often isolated to provide standard reference materials for future product quality assurance testing. These products are often very complex mixtures, requiring separation systems to have a high peak capacity for both analytical and preparative scale separations. A technique gaining popularity among companies that require the isolation of…

Modeling Flow Distribution in Large-Scale Chromatographic Columns with Computational Fluid Dynamics

Column chromatography remains a key unit operation in downstream processing of biopharmaceuticals. For most commercial processes, two to three chromatography steps are used to remove process-and product-related proteins, DNA and adventitious agents. As the biopharmaceutical industry has increased its product offerings and related demands, downstream processes have fast become a bottleneck (1, 2). Many commercial and clinical processes include a number of cycles on one or more chromatography steps to process the harvest from a single production batch. PRODUCT FOCUS:…

The Emerging Generation of Chromatography Tools for Virus Purification

Chromatography media and methods have evolved continuously since their introduction a half century ago. Traditional methods use columns packed with porous particles. They still dominate chromatography applications in the field of virus purification, but the past 20 years have witnessed the ascendance of alternative supports, namely membranes and monoliths. These newer media exploit the familiar surface chemistries — ion exchange, hydrophobic interaction, and affinity — but they use unique architectures that offer compelling performance features. The Architecture of Chromatography Media…