Filtration

Predicting Virus Filtration Performance with Virus Spike Characterization

Evaluating a virus filter should, in theory, be a straightforward exercise. Membrane-based filtration is a robust virus reduction technology that plays an important role in virus safety for most drug production processes. An appropriate virus filter for a given process is generally selected through preliminary testing with relevant drug feed material. Data acquired during such tests are used to determine hydraulic performance targets such as expected flow rates and total throughputs. A virus clearance evaluation study is then performed in…

Single-Use Tangential Flow Filtration in Bioprocessing

    Single-use (SU) components are widely accepted in bioprocessing due in part to improvements in component design, a wider range of products, and increased scalability. Benefits driving their increased use include elimination of cleaning, improved system flexibility, and reduced risk of contamination. Nonetheless, companies now question how far disposables can be incorporated into bioprocessing unit operations. Results of the second annual survey of the bioprocessing market fo single-use solutions showed that >90% of respondents considered filtration well suited for…

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…

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…

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…

Investigating Flow Distribution and Its Effects on Scale-Up

Depth filtration is widely used in the biopharmaceutical industry to purify target proteins by removing whole cells, cellular debris, fines, aggregates, and colloidal particles from the fermentation broth (1,2). At large scale (>2,000 L), culture harvest from a bioreactor is typically processed with a disc-stack centrifuge to remove cells and cell debris. Although centrifugation is very effective for removing whole cells and larger debris, it cannot remove small-size particles, which remain suspended in the centrate. Depth filters are commonly used…

Setting the Stage

Much has already been written lately about addressing the so-called “downstream bottleneck(s).” A number of companies are leading the way toward developing products and platforms for reducing both the costs and the time required for downstream processing. Our task with this special issue was to provide a state-of-the-art update on these activities — but as always, within a limited number of pages allotted. The primary issue behind this bottleneck debacle is to address purification challenges posed by aggregation in cell…

A Presanitized, Purpose-Designed, Single-Use TFF Strategy

    For many years, biopharmaceutical manufacturers have worked to increase capacity, address upstream production issues, and improve product yields. Notable successes recently achieved in upstream technology have significantly increased expression rates and therefore, upstream production capacities. Successes in generating higher titers combined with increasingly stringent quality and regulatory requirements have led to a number of challenges in aligning the efficiency of downstream processing with upstream titers. It is generally recognized that downstream processing costs account for about 70% of…

Use of Membrane Technology in Bioprocessing Therapeutic Proteins from Inclusion Bodies of

The ultimate goal of recombinant fermentation research is cost-effective production of desired proteins by maximizing volumetric productivity (to obtain the highest amount of protein in a given volume in the least amount of time). Bioprocessing for recombinant proteins using genetically modified organisms requires a stable, high-yielding recombinant culture, a highly productive fermentation process, and cost-effective recovery and purification procedures. Escherichia coli has been a widely used host for expression of recombinant proteins (1). Its advantages lie in the enormous data…

The Reoccurrence of Mycoplasma Contamination: Prevention Strategies

    The contamination of microbiological media by mycoplasmas such as Acholeplasma laidlawii is not a recent phenomenon. It has been a major problem with animal-derived sera since the 1980s and has been a concern in the management of cell cultures for decades. The main culprit of serum contamination was the inadequate blood collection methodology and was eliminated with the introduction of hollow collection needles. In addition to the introduction of an improved collection method, serum was filtered with 0.1…