Performance Boost of Bioprocesses
Membrane Chromatography Challenges Traditional Chromatography
Single-use membrane adsorbers are ready-to-use devices that dramatically reduce hands-on time, eliminate packing failures, and obviate the need for cold room storage. Both risk and upfront investments are favorably impacted. At the same time they enhance bioburden control and productivity.
The design of membranes with their open pore structure allows high flow rates. This, in combination with a large frontal surface and small bed height, results in very high throughput while keeping the bed volume small. Typical process data show that throughput in flow-through mode can be two orders of magnitude higher with membrane adsorbers than with columns.
In flow-through mode, conventional chromatography should ideally be run at very high flow rates. These high flow rates can, however, only be achieved by using very large diameter production columns. To achieve a throughput similar to that of membranes, resin-based columns used in flow-through mode thus have a large bed volume and are absolutely oversized for the purpose.
Compared with a column or an ultracentrifuge, a Sartobind® capsule or cassette system is much more compact. Further, they are ready-to-use and therefore easier to set up, which saves hands-on time and reduces plant time.
Membrane adsorbers show benefits especially in flow-through and virus capture applications, where columns are, by force, over-sized. Along with this, large columns require a high upfront investment for the hardware.
Furthermore, membrane adsorbers are disposable (single-use) devices, which reduces storage space and validation costs.
Sartobind® membranes have a pore size of > 3 μm. This allows large proteins, bioparticles, and viruses or virus-like particles to enter the macro-porous membrane structure. Consequently, Sartobind® membrane adsorbers have a 10-times higher binding capacity for viruses, and about 200 times more polishing capacity compared to traditional chromatography columns.
Conventional chromatography beads have a pore size < 100 nm. Small pores limit the access of large molecules to internal binding sites, resulting in a low binding capacity for large biomolecules, blood factors, and viruses or virus-like particles. In addition, columns are operated at 10 to 30 times lower flow rates than membrane adsorbers to allow diffusion into the smaller pores.
Buffer and Time Saving
The positioning of membrane chromatography in downstream processes of monoclonal antibodies and their benefits in flow-through polishing modes have a huge impact on process time (-50%) and buffer consumption (-75%). While columns are usually oversized in these applications, membrane adsorbers decrease COGs more than 60% due to right sizing.
Time and buffer savings are a result of optimal sizing of the membrane adsorber in combination with high flow rates. Conventional packed-bed columns with Q resin have a typical binding capacity of 50-70 g/L and huge diameters are required to reach volumetric flowrates around 100-150 cm/hr. In contrast, membrane adsorbers have a binding capacity of ~10 kg/L with a typical flow rate of 450-600 cm/hr.1
1Li et al., Amgen, J. BioProcessing, 09/10, 23-30, 2005
Chromatography as Easy as Filtration
Membrane adsorbers are ready-to-use and disposable, which avoids packing, cleaning and revalidation. The usage of membrane adsorbers is as simple as using a filter.
The Sartobind® portfolio ranges from 96-well plates and Sartobind® pico for screening, to Sartobind® nano for process development, to capsule and cassettes devices for pilot and production scale.
Different modalities come in either 4 mm or 8 mm membrane bed height, for flow-through polishing and bind & elute applications, respectively. Scale-up with membrane adsorbers is very easy: while maintaining the chosen bed height, the capsule size is simply adapted to process demands. Pressure-flow relationships and the shape of breakthrough curves are identical to the smaller capsule sizes.
Flow-Through Aggregate Removal
The large pores of membranes allow large molecules better accessibility to the ligand. Therefore, Sartobind® Phenyl is beneficial for aggregate removal. It is recommended to use in flow-through mode, which results in 75% less buffer consumption compared to resins.
In hydrophobic interaction chromatography aggregates are removed by using an ammonium sulfate concentration of > 480 mM. By choosing an ammonium sulfate concentration between 230 – 480 mM aggregates will be retained while monomeric mAb will stay in the flow-through.1
Overall, flow-through aggregate removal with membrane chromatography decrease COGs and process time.
1Ebert, S., Fischer-Frühholz, S., Efficient Aggregate, Removal from Impure Pharmaceutical Active Antibodies, BioProcess Int., Vol. 9,(2), 2011, 36-42