APRIL 02 2008

YANNICK BEAUREGARDQUEENIE CHOW

IRENA DOSLO

Diafiltration unit (DF-101) in Monoclonal antibody production

BACKGROUND 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

DIAFILTRATION UNIT (DF-101)

Intelligen., 1991

DIAFILTRATION

Millipore Inc., 2003

DESIGN CONSIDERATIONS

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

TANGENTIAL 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

Millipore Inc., 2003

MEMBRANE SELECTION CRITERIA

Primarily based on size of biomolecule Molecular weight cut off (MWCO) of the

membrane should be 1/3rd to 1/5th of the MW of the molecule to be retained Typical MW of mAb: 150kDa => 30000 MWCO

Other considerations- surface chemistry Membrane flux rate- time factor vs. product

recovery For protein separation: 30 LMH

TYPES OF DIAFILTERS

Flat sheet tangential flow Hollow fibre Tubular Spiral wound

Millipore Inc., 2003

CONTINUOUS 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 1/3rd 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

DIAFILTRATION VOLUME (SUPERPRO MODIFICATIONS)

0 1 2 3 4 5 615

17

19

21

23

25

27

29

88

90

92

94

96

98

100

102

Effect of diafiltration volume on mem-brane area requirement and percent of

acetic acid removal

Membrane Size Removal of Acetic Acid

Diafiltration Volume

Mem

bra

ne A

rea (

m2)

Perc

ent

of

Aceti

c A

cid

rem

oval

FINAL DESIGN Hollow fiber cartridges Membrane area needed

Mem. area = filtrate vol / (filtrate flux * process time)

22.38 m2 with a 5% design consideration

From GE Healthcare services ProCell ultrafiltration unit with 30000

MWCO pore size and seven 3.7 m2 membranes

UNIT NUMBER: Stainless stain housing Steam in place cartridges can be

added

GE Healthcare (2007)

GE Healthcare (2007)

COST

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)

QUESTIONS?Thank you!