A PRIL Y ANNICK B EAUREGARD Q UEENIE C HOW I RENA D OSLO Diafiltration unit (DF-101) in Monoclonal antibody production

B ACKGROUND ON DIAFILTRATION Is a technique that uses basic principles of filtration to completely remove, replace or lower the concentration of salts or solvents from solutions containing biomolecules Uses permeable membrane to separate the components mainly based on size Dilution and concentration Dialysis, column-based gel filtration

Intelligen., 1991

D IAFILTRATION UNIT ( DF -101) Intelligen., 1991

D IAFILTRATION Millipore Inc., 2003

D ESIGN C ONSIDERATIONS Type of flow (tangential vs. direct) Membrane selection Type of diafilter modules Diafiltration volumes Continuous vs. discontinuous flow

T ANGENTIAL VS. DIRECT FLOW Direct Flow: - Large molecule trapped on membrane and forms gel - More susceptible to fouling - Flux rate decreases as volume filtered increases Tangential Flow - Solute diffuses through the surface of the membrane tangent to the flow of the feed - Minimize build up of molecules – less fouling - Prevents rapid decline in flux rate Millipore Inc., 2003

M EMBRANE SELECTION CRITERIA Primarily based on size of biomolecule Molecular weight cut off (MWCO) of the membrane should be 1/3 rd to 1/5 th of the MW of the molecule to be retained Typical MW of mAb: 150kDa => MWCO Other considerations- surface chemistry Membrane flux rate- time factor vs. product recovery For protein separation: 30 LMH

T YPES OF DIAFILTERS Flat sheet tangential flow Hollow fibre Tubular Spiral wound Millipore Inc., 2003

C ONTINUOUS VS. DISCONTINUOUS FILTRATION Continuous Typically constant volume Removal rate of salt = addition rate of water Not the case in SuperPro model Addition of WFI is at 1/3 rd of the removal rate of salt (filtrate) in SuperPro More suited for process scale- requires pumps Discontinuous Concentration and dilution cycles Usually more feasible on a laboratory scale

D IAFILTRATION VOLUME (S UPER P RO MODIFICATIONS )

F INAL DESIGN Hollow fiber cartridges Membrane area needed Mem. area = filtrate vol / (filtrate flux * process time) m 2 with a 5% design consideration From GE Healthcare services ProCell ultrafiltration unit with MWCO pore size and seven 3.7 m 2 membranes UNIT NUMBER: Stainless stain housing Steam in place cartridges can be added GE Healthcare (2007)

C OST Capital cost Equipments Membrane holder Pumps, valves, piping Type of instrumentation Material cost Membrane area Water and chemical usage Labour cost Manual or automatic In SuperPro, the design unit with 3 DV is $56000 GE Healthcare (2007)

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