What is Tangential flow filtration?
Tangential flow filtration (TFF), also known as Cross-flow filtration, is a process of separation widely used in bio-pharmaceutical and food industries. It is different from other filtration systems in that the fluid is passed parallel to the filter, rather than being pushed through a membrane perpendicularly which can clog the filter media. This method is preferred for its continuous filtration and reproducible performance. The particles that pass through the membrane, the permeate, are put off to the side, while the rest, the retentate, is recycled back to the feed.
When is TFF used?
Tangential flow filtration is used in concentration and diafiltration processes.
- Concentration – Increases the concentration of a solution by removing fluids while keeping the solute molecules. This process is done by selecting a filter significantly smaller than the solute molecules to allow for a higher retention of solute molecules.
Diafiltration – The separation of small and large particles, leaving the smaller particles behind without altering the overall concentration at the end by washing out the remaining salt with another buffer. This process can also reduce the concentration of a solution by washing out the remaining salts with water.
Specific applications of TFF include, but are not limited to:
- Pre-filtration component WFI systems to remove endotoxins.
- Recovering of bacterial cultures and viruses.
- Removing PVA that is excreted from the excipient from nanoparticles during drug loading.
References
Carole S. Genovesi, May-June 1983, Several Uses for Tangential-Flow Filtration in the Pharmaceutical Industry, Accessed on 28 August 2018. <http://journal.pda.org/content/37/3/81.abstract>
Pall Corporation, n.d., Introduction to Tangential Flow Filtration for Laboratory and Process Development Applications, Accessed on 28 August 2018. <https://laboratory.pall.com/content/dam/pall/laboratory/literature-library/non-gated/id-34212.pdf>
Gautam Dalwadi and Vivian Bruce Sunderland, 26 September 2008, Purification of PEGylated Nanoparticle Using Tangential Flow Filtration (TFF), Accessed on 28 August 2018. <https://www.tandfonline.com/doi/full/10.1080/03639040601180143?scroll=top&needAccess=true>
Novasep, n.d., Industrial cross-flow filtration technology (Picture), Accessed on 28 August 2018. <https://www.novasep.com/technologies/industrial-cross-flow-filtration-technology.html>