Membranes – With the Perfect Pleats for Performance

Related Vendors

Italvacuum, Srl

TRM Filter d.o.o.

ProMinent GmbH

Sartorius AG

The presence of white patches means that up to 30 per cent of the membrane was inaccessible to the liquid and consequently, unused in filtration. This has a negative impact on total throughput and also on the basic scalability of such filters.

Scalability of Filter Processes

Direct linear scale up from small elements to large process-scale filters requires comparable performance data per membrane area. This is the case for the new cartridge. Even the smallest pleated elements (size 4 capsule, 0.021 m²) show the same total throughput per square meter of filter area as a 30’’ cartridge with 3m². Therefore, linear scale up during the different stages of product development is guaranteed, allowing processes to be optimized. However, this can be completely different for filters in which the membrane area available is not entirely used during filtration.

Reliable Membrane Wetting

Reliable wetting is required for integrity testing of sterilizing-grade filters. For the new filter, it was possible to reduce the required quantity to only 5 liters per 10’’ cartridge. The exceptionally hydrophilic nature of the surface modified PES

membrane is the reason for the excellent wetting behavior of the filter.

Why is this so important for process efficacy? In most cases, water for injection (WFI) is used for wetting. WFI itself costs least €3-5 per liter. According to the wetting instructions of many filter manufacturers (5 min of wetting at 300 mbar), roughly 100 liters of WFI costing €300–€500 are required to wet out a single 10’’ cartridge reliably. Due to the unique wetting behavior of Sartopore Platinum, fewer than 5 liters of WFI are required for a 10” cartridge, meaning a drastic reduction in WFI usage of 95 per cent. This saves at least €250 per 10” cartridge.

Increasing Product Yield

This filter has the lowest unspecific adsorption of all PES cartridges available on the market. But what does this mean regarding cost reduction? For a protein valued at €500-1,000 per gram, loss of yield directly due to unspecific adsorption can be calculated.

By testing the adsorption of mAbs, it was found that this unspecific adsorption was 0.16g per 10’’ cartridge for Sartopore Platinum. The identical test protocol for other cartridge resulted in an adsorption of 0.44g per 10’’ cartridge. This means that an additional 0.28g mAb is lost during filtration. Considering the above-mentioned cost of €500-1,000 per gram of protein, this corresponds to an additional loss of yield totaling €140-280 per 10” cartridge. Of course, the specific quantity of loss in yield depends on the particular protein, cartridge type and membrane area. But this example already shows the importance of factors like unspecific adsorption that impact total process costs.

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