Downstream Processing

How Pore and Fibrous Interstice Structure Influence Filter Performance

    When bioprocess liquids bearing suspended particles are filtered, retained particles can block and clog membrane filter pores. The pore size rating of a filter should be selected to retain objectionable particles by sieving, and the aptitude of its polymeric composition for adsorptive sequestration of those particulates also needs to be known. The quantity and nature of retained particles require accommodation if filtrative removal is to be considered successful. Too extensive a particle load will prematurely block a filter’s…

Improving IEX Throughput and Performance with Differentiated Chromatography Sorbents

    Optimized upstream processing and high-productivity cell culture increase not only target protein titers, but also impurity and contaminant concentrations to be removed from large volumes of feedstock. Simultaneously, biopharmaceutical drug production is increasingly driven by manufacturing cost reduction. These facts together increase the pressure on downstream processing and create an urgent need for more productive and streamlined chromatography operations. Key parameters to consider for enhanced process economics in chromatography are higher protein binding capacities at high flow rates…

How Pore and Fibrous Interstice Structure Influence Filter Performance

    A common objective in pharmaceutical processing is the removal of solids from fluid suspensions through filtration. The usual purpose is the removal of the solid particles to a specified extent, within a given time interval, at the largest possible throughput. Attainment of those goals is managed by proper selection of filtration conditions: principally an adequate effective filtration area (EFA) as defined by filter porosity and a proper rate of flow as regulated by applied differential pressure (ΔP) over…

Single-Use Connections Enable Advancements in Aseptic Processing

    Today’s market demand for new drugs — combined with the difficult economic environment — is challenging bioprocessors to review their manufacturing systems and seek ways to make them more flexible, reliable, and cost effective. Increasingly, biomanufacturers are turning to single-use aseptic processing systems to meet or beat aggressive product-introduction timeframes while controlling costs. Innovative new single-use technologies continue to be introduced, giving pharmaceutical companies greater flexibility for replacing traditional stainless tubing, equipment, and even entire process suites with…

Using In-Line Disposable Pressure Sensors to Evaluate Depth Filter Performance

    Development of a recovery process for a fed-batch mammalian cell culture product involves several objectives: process scalability, robustness, maximizing product yield, elimination of subsequent purification steps, and low cost of goods. In an effort to achieve those objectives, we developed a three-stage primary recovery process to remove biomass and clarify the feed stream for downstream column chromatography (Figure 1). The initial stage involves removal of whole cells and larger cellular debris using a continuous disc-stack centrifuge. Depth filtration…

Minibodies and Multimodal Chromatography Methods

    Small, genetically engineered immunological constructs are being developed industry-wide for a growing range of in vivo applications. Examples include Fab, F(ab’)2, single-chain (sc) Fv, bis-scFV, diabodies, minibodies, and single-domain antibodies (1). Their small size potentially gives them access to tissues that are poorly accessible by intact antibodies; rapid clearance from blood and nontargeted tissues; lower immunogenic response; and eye-drop, inhalant, or oral administration. We report here on purification of an affinity-matured, humanized, antiprostate stem-cell antigen (PSCA) minibody for…

Novel Affinity Ligands Provide for Highly Selective Primary Capture

    Downstream processing of biopharmaceuticals is costly and time-consuming, often involving multiple steps with significant time and energy expended on maximizing product quality and yield. Affinity chromatography is one of the simplest and most effective methods for purifying protein and peptide therapeutics, offering reduced process steps and therefore higher yields than nonaffinity methods can provide. Protein A is widely used for affinity purification of monoclonal antibodies (MAbs), Fc fragments, and Fc fusion proteins. But it is a challenge to…

Primary Clarification of Very High-Density Cell Culture Harvests By Enhanced Cell Settling

    In recent years biopharmaceutical manufacturing has demonstrated major improvements in MAb production, exhibiting product titers as high as 25 g/L often associated with very high cell densities (1). High-density cell cultures with >150 million cells/mL pose a great challenge in clarification and further downstream processing because of a need to remove a large amount of biomass and increased levels of contaminants from cell debris generated during cell culture and harvesting. Production of biological substances (MAbs, in particular) usually…

PAT-Based In-Line Buffer Dilution

    Technological advancement has taken protein expression titers from concentrations measured in mg/L to those measured in g/L over just a few years (1). Annual demand for antibodies has reached several metric tons, which has spurred production of >100 kg batches of protein at a time (2). As upstream yields continue to increase, downstream purification involving process solution preparation and delivery must increase in proportion to keep pace with demand. That has placed facility and instrumentation capacity constraints front…

Questioning the Downstream Bottleneck

In preparing for our October supplement on bioprocess design, BPI’s contributing editor Lorna D. McLeod spoke with Bayer Healthcare’s Harald Dinter (vice president of global biological development) and Jens Vogel (CMC development team leader and head of isolation and purification in global biological development) about the downstream bottleneck. Is it or isn’t it a real problem? Does the answer depend on your point of view? BPI: “Does a company’s downstream capacity place practical constraints on increasing production titers? Is that…