Single-pass Tangential Flow Filtration Research Articles

Single-use, single-pass tangential flow filtration using low-cost hollow fiber modules

Increasing pressures on biomanufacturing costs have led to renewed interest in the development of single-use technologies that can be readily adapted to continuous processing. The objective of this study was to use commercially available hollow fiber membranes, originally designed for high-flux hemodialysis, for single pass tangential flow filtration with high conversions. Experiments were performed with solutions of Immunoglobulin G (IgG) using polysulfone hollow fiber membrane cartridges with a surface area of 1.9 m2. The hollow fiber modules were able to provide more than 10-fold concentration of IgG in a single-pass with exit concentrations greater than 200 g/L. Stable operation was achieved during a continuous run for over a 120-h period with feed side pressure drops less than 1 kPa and transmembrane pressure drops less than 60 kPa. A single dialyzer was able to process 1.4 kg of IgG per day with a total cost of less than $0.004 per g of IgG. Flux-pressure profiles were in good qualitative agreement with a simple model accounting for concentration polarization effects and the variation of flux and pressure with axial position in the module. These results clearly demonstrate the potential of using these low-cost single-use hollow fiber modules for single-pass tangential flow filtration in continuous biomanufacturing.

Investigating the combination of single‐pass tangential flow filtration and anion exchange chromatography for intensified mAb polishing

There is growing interest within the biopharmaceutical industry to improve manufacturing efficiency through process intensification, with the goal of generating more product in less time with smaller equipment. In monoclonal antibody (mAb) purification, a unit operation that can benefit from intensification is anion exchange (AEX) polishing chromatography. Single-pass tangential flow filtration (SPTFF) technology offers an opportunity for process intensification by reducing intermediate pool volumes and increasing product concentration without recirculation. This study evaluated the performance of an AEX resin, both in terms of host cell protein (HCP) purification and viral clearance, following concentration of a mAb feed using SPTFF. Results show that preconcentration of AEX feed material improved isotherm conditions for HCP binding, resulting in a fourfold increase in resin mAb loading at the target HCP clearance level. Excellent clearance of minute virus of mouse and xenotropic murine virus was maintained at this higher load level. The increased mAb loading enabled by SPTFF preconcentration effectively reduced AEX column volume and buffer requirements, shrinking the overall size of the polishing step. In addition, the suitability of SPTFF for extended processing time operation was demonstrated, indicating that this approach can be implemented for continuous biomanufacturing. The combination of SPTFF concentration and AEX chromatography for an intensified mAb polishing step which improves both manufacturing flexibility and process productivity is supported.

Model-Based Design and Process Optimization of Continuous Single Pass Tangential Flow Filtration Focusing on Continuous Bioprocessing

In this study the Single-Pass-Tangential-Flow-Filtration (SPTFF) concept for continuous ultrafiltration in bioprocessing is investigated. Based on a previously validated physico-chemical model for a single ultrafiltration cassette, the transfer to a multistage SPTFF is predicted and validated experimentally by concentration steps for bovine serum albumin (BSA) and the monoclonal antibody immunoglobulin G (IgG) are compared. The model applied for the ultrafiltration membrane contains the Stagnant Film Model (SFM) for concentration polarization, as well as the Osmotic Pressure Model (OPM) and the Boundary Layer Model (BLM) for the mass transfer through the membrane. In addition, pressure drop correlations as a function of the Reynolds number are included to describe the development of the transmembrane pressure over the length of the module. The outcome of this study shows the potential to improve this multi-parameter dependent unit operation by a model-based optimization allowing significant reduction of experimental efforts and applying the Quality by Design (QbD) approach consistently. Consequently, a versatile tool for conceptual process design is presented and further application is discussed.

Ultrafiltration behavior of partially retained proteins and completely retained proteins using equally-staged single pass tangential flow filtration membranes.

This work examines the ultrafiltration behavior of partially retained proteins like lysozyme and completely retained proteins like monoclonal antibodies using single pass tangential flow filtration (SPTFF) modules with different screen channels and molecular weight cut-offs. When the staging of the SPTFF used the same membrane area in each stage, there was no impact of the module screened channel or the buffer matrix on the final concentration achieved for completely retained monoclonal antibodies. A hybrid configuration containing 30 kDa membranes and 50 kDa membranes increased the maximum achievable concentration for both the monoclonal antibodies used in this work, at the same time, allowing a two-fold to four-fold increase in normalized feed flow-rate through the system compared to only the 30 kDa or only the 50 kDa membranes. The sieving coefficient of lysozyme measured and calculated using SPTFF was lower than those measured during conventional recirculation TFF indicating a more complicated concentration polarization effect than conventional recirculation TFF. Moreover, the sieving coefficients of lysozyme were the same for the 10 kDa regenerated cellulose and 50 kDa PES membranes while it was higher for the 30 kDa regenerated cellulose membrane. The difference in TFF and SPTFF behavior is important when the product of interest is desired to be permeated. This work presents the first body of data for partially and completely retained solutes together in the SPTFF mode and provides a strategy to increase protein concentration at higher feed flow rates. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 2018 © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1137-1148, 2018.

Leveraging single-pass tangential flow filtration to enable decoupling of upstream and downstream monoclonal antibody processing.

Decoupling upstream and downstream operations in biopharmaceutical production could enable more flexible manufacturing operations and could allow companies to leverage strategic or financial benefits that would be otherwise unattainable. A decoupling process was developed and scaled up utilizing single-pass tangential flow filtration for volume reduction, followed by bulk freezing in single-use bags prior to purification. Single-pass tangential flow filtration can be used to continuously concentrate harvested cell culture fluid, reducing the volume by 15-25× with a step yield of >96%. These concentration factors were reproduced with a second product, indicating that the process could be amenable to platform processes. Experimental data indicate that the product tested was stable for at least one year at -40 or -70°C. The concentration of the harvested cell culture fluid-either with or without a subsequent period of frozen storage-had no impact on the product quality attributes that were tested. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:405-411, 2018.

Investigation of single-pass tangential flow filtration (SPTFF) as an inline concentration step for cell culture harvest

This work examined the use of single-pass tangential flow filtration (SPTFF) to concentrate cell culture harvest. Conventional tangential flow filtration (TFF) is routinely used in biotechnology and related industries to concentrate protein solutions and exchange them into the final formulation buffer. However, several pump passes and a recirculation skid are required to achieve the target concentration in conventional TFF. Thus, it is impractical to implement TFF for inline concentration of protein solutions during the manufacture of biologic products. New developments in the biotechnology industry have focused on using ultrafiltration in a single pump pass (also known as SPTFF) to concentrate protein solutions in a single pump pass as an inline concentration step. There is thus a potential utility for this technology to overcome manufacturing bottlenecks. While there is limited work in literature describing the use of SPTFF for concentration of in-process protein pools, no work has been reported on the use of SPTFF for concentration of cell culture harvest and the challenges faced in this situation. This work examines the utility of using a 30kDa ultrafiltration membrane in the SPTFF mode to concentrate cell culture harvest for six different biologic assets in order to determine its feasibility over a wide range of biologic cell culture harvest streams. Cell culture harvest provided unique challenges to SPTFF that were overcome using a synthetic adsorptive hybrid filter technology. In particular, the hydraulic conditions necessary to achieve a targeted concentration factor varied from lot-to-lot for the same molecule. This caused difficulty in implementing a given set of operating conditions for the same molecule because of process instability. To address these challenges, we used high capacity adsorptive filters that effectively reduced both particulates and soluble contaminants during primary recovery to improve the SPTFF performance. The adsorptive filter mainly removed process related impurities, specifically HCP and DNA that prematurely fouled the ultrafiltration membrane and changed the capacity of SPTFF. The adsorptive filter also eradicated cell-culture lot-to-lot performance variability with SPTFF by offering a relative standard deviation of <10%. The use of SPTFF by simultaneously coupling the clarification with the concentration was successfully demonstrated. This is the first work to report the use of SPTFF to concentrate cell culture harvest for six different biologic assets, overcoming challenges using adsorptive filtration, and demonstrate debottlenecking for manufacturing.

Single pass tangential flow filtration to debottleneck downstream processing for therapeutic antibody production

As the therapeutic monoclonal antibody (mAb) market continues to grow, optimizing production processes is becoming more critical in improving efficiencies and reducing cost-of-goods in large-scale production. With the recent trends of increasing cell culture titers from upstream process improvements, downstream capacity has become the bottleneck in many existing manufacturing facilities. Single Pass Tangential Flow Filtration (SPTFF) is an emerging technology, which is potentially useful in debottlenecking downstream capacity, especially when the pool tank size is a limiting factor. It can be integrated as part of an existing purification process, after a column chromatography step or a filtration step, without introducing a new unit operation. In this study, SPTFF technology was systematically evaluated for reducing process intermediate volumes from 2× to 10× with multiple mAbs and the impact of SPTFF on product quality, and process yield was analyzed. Finally, the potential fit into the typical 3-column industry platform antibody purification process and its implementation in a commercial scale manufacturing facility were also evaluated. Our data indicate that using SPTFF to concentrate protein pools is a simple, flexible, and robust operation, which can be implemented at various scales to improve antibody purification process capacity.

Protein concentration with single-pass tangential flow filtration (SPTFF)

This paper presents a novel Cadence™ single-pass tangential flow filtration (SPTFF) process for protein concentration, operating in a continuous mode. The main advantages of the SPTFF technology have been highlighted in a benchmark comparison test versus conventional TFF. SPTFF modules consist of internally staged T-series cassettes for creating longer flow paths that result in significantly higher conversion in one pass. This eliminates the need for the conventional TFF recirculation loop. SPTFF utilizes flow ratio control to achieve target concentration factors and final product concentrations instantaneously. Bovine IgG solutions in PBS (5–45 g/L) were processed to achieve a concentration factor range of 3–25×, which resulted in permeate fluxes in the range of 10–70 L/m 2/h over a feed-side pressure drop range of 25–65 psid. Ten cycles of high concentration, product recovery and cleaning were successfully completed with the same SPTFF module to demonstrate experimental reproducibility and process stability. A ∼45 g/L IgG feed solution was concentrated to 190–225 g/L during all cycles resulting in high product recoveries in the range of 95.7–98.9%.

TFF system improves recovery and increases yield

US filtration, separation and purification company Pall Corp has launched what it claims is the industry's first single-pass tangential flow filtration (TFF) product designed to optimise downstream purification steps in either single-use or reuse modes of operation.