Watson-Marlow Fluid Technology Group has supplied peristaltic pumps to Novasep for its  Sius™ TFF Skid, a tangential flow filtration system used in the biopharmaceutical industry to separate and concentrate biomolecules according to their size. The new skid is the first on the market to offer a 100 per cent single-use TFF solution. Watson Marlow 520UN/R2 and 620UN/RE pumps were selected to facilitate the system’s fluid transfer operations.

In tangential flow filtration (TFF), the fluid to be processed circulates across a porous membrane and, under pressure, passes through its pores. Molecules of a greater size than the pores remain in the retentate, whereas small molecules pass through the membrane into the permeate. The retentate circulates continuously in a loop travelling across the membrane which, for example, enables the molecules to be concentrated or facilitates buffer exchange (diafiltration).

Recirculation duties

The recirculation loop (retentate) is fed by a Watson-Marlow 520UN/R2 continuous tubing pump as part of diafiltration, delivering replacement buffer to stream. While a 620UN/RE LoadSure tube element pump is used to recirculate the retentate within the loop, providing low-pulse flow rates and a linear 4 bar displacement pressure, to enable easy setting of the system rentate valve. The advantage provided by these two pumps is that they ensure cells are undamaged through excessive heat transfer and unwanted particulates are not introduced into the fluid stream. Furthermore, peristaltic technology eliminates cross-contamination risks.

“In this type of application, purity and quality are key factors,” says Mr Chevalier, Process Engineer at Novasep. “Therefore, the cleaning phases are very important in order to ensure that the equipment complies with hygiene specifications. The Watson-Marlow pumps’ tubing provides high-purity, USP Class VI validated contact materials.

Watson-Marlow tubes are pre-sterilised (gamma irradiated) so that the user can eliminate the cleaning and validation phase without risk of contamination. This saves a great deal of time and has a direct effect on operating costs.

Accurate fluid delivery

“The second advantage of Watson-Marlow pumps is that they offer a high degree of precision, even at higher pressures,” adds Mr Chevalier. “This has enabled us to leave out the flow meter that we had planned originally.” 

Novasep, which has its global headquarters in Pompey, France, supplies products for the manufacture of synthetic molecules and biomolecules used in the pharmaceutical, food processing and chemical industries. The company’s Sius™ TFF Skid is composed entirely of single-use components, all of which are pre-sterilised and ready to use. Novasep has also developed a system to facilitate the performance of integrity tests that validate the assembly in-situ.

Sius™ TFF Skid covers all tangential filtration requirements from the research and development stages through to commercial production thanks to its compact design and available range (0.1–2.0 m²). The system has been developed completely by Novasep and is supplied with all the validations required to work in a CGMP environment.