reliable and predictable scale-up of unit operation in

Bala Raghunath, Ph.D.

Asia Seminar Series

Dec, 2015

RELIABLE AND PREDICTABLE SCALE-UP OF UNIT OPERATION IN BIOLOGICS PROCESSING

2

■ Background

■ Approach to successful scale-up

■ Practical scaling techniques

■ Case study

■ Avoiding pitfalls

Outline

3

…an increase according to a fixed ratio..…Merriam Webster

What is Scale-Up?

4

…an increase according to a fixed ratio..…Merriam Webster

What is Scale-Up?

“The successful startup and operation of a commercial size unit whose design and operating procedures are in part based upon

experimentation and demonstration at a smaller scale of operation”

…...A. Biseo- Reliable Process Operation at Desired Scale- Meet project deadlines and capacity requirements- Ensure regulatory compliance- Meet economic targets

- Process Development

• PD should begin w/

the scaling end in mind

Make large quantities of materials having same

properties as those that were made on the small scale

5

What is Scale-Up?

3 L 200 L 10,000 L

How do we duplicate our results* at the larger scale?

*product characteristics, quality, consistency

6

■ Process – Chemistry, Physics or Thermodynamics

Binding Characteristics (Charge, equil constant, zeta potential)

Physical Characteristics (Size, membrane/resin pore)

Other effects (CIP, extractables)

■ Operation – Procedures, control strategy

Parameters (KLa, agitator tip speed, pressure, flow, flux, loading, HETP)

Mode (Auto vs Manual, Pressure vs Flow control, process control strategy)

Other effects (Facility constraints, Safety considerations, Aseptic practices)

■ System – Equipment, instrumentation, processing strategy

Manufacturing strategy (Single Use vs Stainless Steel, Use of existing equipment)

Equipment configuration (Module type, piping, tank, pump, instruments, agitator type)

Other effects (Matl. Of Construction: acrylic, SS columns, location)

Scale-up PurviewThe Heart of the Process

Accessorial Dimension Across Scales

7

■ Examine and specify “similarity”, at critical levels, between the small and large scale systems

Geometric: shape (l, w, h)

Mechanical: pressure, velocity (flow), time

Thermal: temperature

Chemical: Concentration

Approach for Successful Scale-up

H1

D1

H2

D2

2

2

1

1

D

H

D

H

M

Vs

V-eL

L

Vt

A

n M

n Vs

n V-eL

L

n Vt

n A

protein mass

sample volume

elution volume

column length

bed volume

cross sect. area

Q

Q/A

n Q

Q/A (since n Q/n A)

volumetric flow rate

linear velocity

Maintain certain critical or key process parameters equivalent at

corresponding points between the small and large scale systems

‘The Similarity Principle’

8

■ Express the “similarity” as a criteria:

Simple ratio of measurement, fluxes or forces – the ‘scaling rule’

► Scaling rule → ensures critical process parameters are maintained same

between small and large scale systems

Approach for Successful Scale-up

9

Scaling Rules – Some Examples

Criteria Mathematical

Depth FiltrationSame separation (Protein-Particle),

Productivity

Maintain same Resistance, R

R = Resistance, DP = Pressure Drop, Q = Flux, V =

Throughput

Same Flux (Q),

Same Pressure Drop (DP)

Increasing Filter Area(Same fi l ter depth; Increase

length, breadth)

Tangential Flow FiltrationSame separation (Protein-Buffer),

Productivity

Maintain same Polarization

PI = Polarization Index, Cw, Cb = Wall and bulk Protein

Concentration, J = Perm Flux, k = f(Q) = M/T Coeff, Q =

Same Permate Flux (J),

Same Crossflow (Q)

Increasing Filter Area(Same Channel length,

height; Increase Channel

width)

Chromatography

Same separation (Protein-Protein,

Protein-Molecular Impurity),

Productivity

Maintain same No of Plates (N), Loading

N = No. of theoretical plates, L = Column Height , Q =

Flow Rate , H = HETP, v = velocity, A, C = constants, A’ =

Col CS Area, C’ = Concentration

Same Bed-Heght (L), Packing (A), Fluid (n)

Same Load (gms of Protein/Resin vol)Increasing Resin Volume

(Increase Bed diameter)

Unit Operation PracticeScaling Rule

Scale by

43

2

2

3

1 aVaVaVa Q

P R D

CQ L

A

1

H

L N

LA

CA

L

gLoad

'

''

media

protein v

10

Linear

Predictive

Hybrid

Flow pathFlow path

X 12 X 10

Flow path

- Scale-down element

Need a valid (tested, verified) “scale-down model”

Practical Scaling Techniques (for ensuring similarity)

11

Linear

Predictive

Hybrid

- Uses a well developed or tested model


12

Linear

Predictive

Hybrid - Has elements of both Linear and Predictive

0

5

10

15

20

25

0.0 1.0 2.0 3.0 4.0

Process Time, h

Co

ncen

trati

on

, g

/L PD Loading

= 50 L/m2

Manuf. Loading

= 200 L/m2

TFF

Same Flux

Same Cross-flow

Varying loading

during initial scale-up

(to be verified)


13

Scaling:

■ Use scale-down testing with ‘predictive equation’ or linear scaling using linear scale-down element to screen filters/resins and estimate full-scale sizing requirements

■ Simulate the process at Pilot or lab scale using proposed process loading, flows, solution conditions etc

General “Best-Practices” Scale-Up Approach

Small Scale Testing

Scale Up To Manuf. Plant

On Paper(Optimization)

Simulate and/or Run In Pilot Plant or Small Scale(Verification)

Finalize Manufacturing

Scale Design

- ROBUSTNESS

- OPER. RANGES

“Predictive/linear” Linear

14

Refers to

■ Equipment effects: Tank, pump, device holder/format, column type, dead-legs/hold-up, air-

liquid interface, line-size, location/height differences, matl. of construction, agitator type…

■ Processing strategy: Auto vs Manual, constant pressure vs flow, control strategy for feed, buffer

preparation, CIP chemical mixing and addition strategy…

■ Process constraints Facility fit, use of existing equipment, safety considerations,

aseptic/sanitization practices, CIP sequence, limits on process pressure, flowrate.

System & Other Processing Considerations

– Experience, ‘best practices’ guidelines are used to ensure that these differences do

not pose or lead to scaling issues

– However, these are the areas where scaling ‘snafus’ (mistakes) often occur

─ Scaling Rule─ Case study

3.5 cm2 6,900 cm2

NORMAL FLOW FILTRATION (NFF)

16

Ensure same separation*, same plugging or flow-throughput profiles across scales

NFF Scaling Rule

How do we ensure this?

* Particle/microorganism from protein

17

NFF Scaling Rule

Geometric

Mechanical

Thermal

Chemical

Approach

V = Vol throughput at time t = lit/m2

Qi = Initial Flow Rate = lit/m2-hVmax = Max Vol Throughput = lit/m2

t = time, h

Plugging profile for most biological fluids is represented by gradual pore

plugging model (Vmax method)

Throughput Profile:

18

NFF Scaling Rule

Geometric

Mechanical

Thermal

Chemical

Approach

V = Vol throughput at time t = lit/m2

Qi = Initial Flow Rate = lit/m2-hVmax = Max Vol Throughput = lit/m2

t = time, h

Plugging profile for most biological fluids is represented by gradual pore

plugging model (Vmax method)

V, L

/m2

T, h1 20

PD

0.25(15 min)

Assume (Predict) Filtration

will continue on this line

1.5

V*

Amin = VBatch/V*

Scale-upThroughput Profile:

NFF Scaling – Avoiding Pitfalls (Case Study)

Existing Process: Calf serum filtration

“Optimized” Process: Calf serum filtration

■ Sizing estimated using Vmax testing of Prefilter & Sterile filter at small scale

47 mm scale (13.8 cm2), DP = 1 bar, “Vmax test” for 10 min

20

5 m PVDF Prefilter

(0.2 m2)

0.22 m PVDF Sterile

filter

(2.76 m2)

Issue: FrequentPlugging of 0.22 mSterilizing grade filter.

Proposed Solution:“Re-optimize” Prefitler

2.76 m2 x 2 = 5.5 m2

2/1.2m

glass/cellulose

Prefilter

(1.39 m2)

0.22 m PVDF Sterile

filter

(0.69 m2)

Area decreased

> 2.5 times!


21

V

Time

Prefilter47 mm Scale

DP = 1 bar

Sterile Filter47 mm Scale

DP = 1 bar

Target ‘Volume’100

Prefilter + Sterile FilterManufacturing Scale

DPTotal = 0.7 bar

Throughput

Not realized!

Premature

Plugging!

22

Issue: ■ Manufacturing Scale pressure constraint = 0.7 bar not considered during

Small Scale testing


V

Time

Prefilter47 mm Scale

DP = 1 bar

Sterile Filter47 mm Scale

DP = 1 bar

Target ‘Volume’100

Prefilter + Sterile FilterManufacturing Scale

DPTotal = 0.7 bar

Throughput

Not realized!

Premature

Plugging!



“ Optimized” Process: Calf serum filtration



23

5 m PVDF Prefilter

(0.2 m2)

0.22 m PVDF Sterile

filter

(2.76 m2)



2.76 m2 x 2 = 5.5 m2

2/1.2m

glass/cellulose

Prefilter

(1.39 m2)

0.22 m PVDF Sterile

filter

(0.69 m2)



“ Optimized” Process: Calf serum filtration



24

5 m PVDF Prefilter

(0.2 m2)

0.22 m PVDF Sterile

filter

(2.76 m2)



2.76 m2 x 2 = 5.5 m2

2/1.2m

glass/cellulose

Prefilter

(1.39 m2)

0.22 m PVDF Sterile

filter

(0.69 m2)

Re-

0.22 m PVDF Sterile

filter

(1.38 m2)

0.7

Area still decreased

2 times!

0.1 m2 80 m2

TANGENTIAL FLOW FILTRATION─ Scaling Rule─ Case study

26

Ensure same separation* and productivity at both scales

‘Similar’ concentration profiles

What are these concentration profiles and how do we express them?

TFF Scaling Rule

* Protein-Buffer

Polarization Profile

lnX R N R1 exp C

CObsObs

o

bulk

f

bulk Operating Profile

DF UF

QF

TMP Qf = J x A

QR

Cb

Cw

membrane

membrane

k

DPCf

Concentration Profiles in a TFF Process

27

28

For equivalent polarization profile (Cwall/gel/Cbulk), maintain constant

J or production rate (liters/m2-hr)

K or mass transfer coefficient (i.e. crossflow rate)

For equivalent operating profile, maintain constant

X, N

Order or sequence of X, N

loading (process time)

Increase module width, w, i.e. module area, from small to large scale to accommodate larger load

Executing’ the Scaling Rule for TFF Processes

Geometric

Mechanical

Thermal

Chemical

Approach

Flow pathFlow path

Flow path

W WW

W

29

Optimum values chosen from small scale studies:

TMP = 8 psi and Flux = 30 lmh (QF = 325 lmh)

Process control (Large Scale) based on TMP set-point

Target TMP value = 8 psi

TFF Scaling – Avoiding Pitfalls (Case Study)

0

10

20

30

40

50

60

0 5 10 15 20 25 30

TMP, psi

Flu

x, lm

hPLCGC, 5 oC

30

Scaling Up with TMPsetpoint = 8 psi

DPValve

TMP

DPM

QF

PF

PR

PP

Retentate

valve

Permeate

Feed

QRDiafiltration

buffer

Feed

Tank

QP

Retentate

DPSystem

PSystemValveM P P P

2

P TMP DDD

RFM P P P D

31

Scaling Up with TMPsetpoint = 8 psi

PP P P 2

P TMP

SystemValve

M DDD

PP = 0 psi

Psystem = 2 psi

ΔPvalve control to obtain PR and in turn, TMP

Simple Case: If retentate valve is fully

open, DPvalve = 0 psi

PR = ΔPvalve + ΔPsystem

PR = 0 psi + 2 psi = 2 psi

ΔPM ~ feed flow rate QF

ΔPM = 6-18 psi ………… (specification)

Case 1 (ΔPM = 6) TMPMin = 3 + 0 + 2 − 0 = 5 psi

Case 2 (ΔPM = 18) TMPMin = 9 + 0 + 2 − 0 = 11 psi

Set-point not obtainable in Case 2!

Control to 3 psi to get

desired TMP = 8 psi

DPValve

TMP

DPM

QF

PF

PR

PP

Retentate

valve

Permeate

Feed

QRDiafiltration

buffer

Feed

Tank

QP

Retentate

DPSystem

32

Release DP of the modules

DP distribution for two PLCGC Cassette Lots

0

0.05

0.1

0.15

0.2

0.25

0.3

4 6 8 10 12 14 16 18 20

DP (QC Release), psi

Pro

bab

ilit

y D

istr

ibu

tio

n)

P4BN8659P4BN0989

Low Spec High Spec

PD Studies Manufacturing

• Scaling Rule• Case study

CHROMATOGRAPHY

34

Ensure same separation* (yield and purity) and productivity across scales

How do we ensure this?

Ensure same separation* (yield and purity) and productivity across scales

Chromatography Scaling Rule

* Protein-Protein

35

Scale-up relationships

CQ L

A

1 N

n

C A

L

H

L N

LA

CA

L

gLoad

'

''

media

protein v

Separation Efficiency (N) (Van Deemter)

Elution

Loading

N = No. of theoretical plates

L = Column Height = m

Q = Flow Rate = cv/h

H = HETP, Height equivalent of a Theoretical Plate = m

A, C = constants

v = velocity = cm/hr

A’ = Col CS Area, m2

C’ = Concentration, g/L

36

For equivalent separation* (yield and purity) and productivity

across scales :■ Need to ensure same N (efficiency or plates) and Loading

(gprotein/Lmedia) across scales

‘Executing’ the Scaling Rule for Chromatography

Geometric

Mechanical

Thermal

Chemical

Approach

37

n

C A

L

H

L N

Chromatography Scale-up – Method 1* (keep bed height constant across scales)

For equivalent plates, N, keep

■ L (bed height) same across scales

■ H (HETP) same across scales

v (velocity, cm/hr) same across scales

Same resin (particle characteristics) and fluid characteristics (conc. etc)

Same ‘packing’ at both scales (?!)

Keep normalized load same across scales:

■ gprotein/Lmedia is constant

Increase column diameter, i.e. resin volume, to accommodate larger load

38

n

C A

L

H

L N

Chromatography Scale-up – Method 1* (keep bed height constant across scales)

For equivalent plates, N, keep

■ L (bed height) same across scales

■ H (HETP) same across scales

v (velocity, cm/hr) same across scales

Same resin (particle characteristics) and fluid characteristics (conc. etc)

Same ‘packing’ at both scales (?!)

Keep normalized load same across scales:

■ gprotein/Lmedia is constant

Increase column diameter, i.e. resin volume, to accommodate larger load

MVs

Ve

sample mass

sample volume

elution volume

nMnVs

nVe

LVc

A

column length

column volume

cross sect. area

LnVc

nA

QQ/A

volumetric flow rate

linear velocity

nQQ/A (since nQ/nA)

Scaling factor = "n"

39

CQ L

A

1 N

Chromatography Scale-up – Method 2 (keep residence time constant across scales)

Where:- Q = v/L

- tR = residence time = 1/Q

For equivalent residence times, keep■ Q (cv/hr) same across scales

Change L (column height) and v (velocity, cm/hr) to keep Q constant

(Note: when Q is constant and L changes, N does not truly remain constant; typically use smaller column L (lower N) at SS and higher L (higher N) at larger scale → safety

factor)

■ Same resin (particle characteristics) and fluid characteristics (conc. etc)

Keep normalized load same across scales:■ gprotein/Lmedia is constant

Increase both column diameter/length, i.e. resin volume, to accommodate larger load keeping Q constant

40

CQ L

A

1 N

Chromatography Scale-up – Method 2 (keep residence time constant across scales)

Where:- Q = v/L

- tR = residence time = 1/Q

For equivalent residence times, keep■ Q (cv/hr) same across scales

Change L (column height) and v (velocity, cm/hr) to keep Q constant

(Note: when Q is constant and L changes, N does not truly remain constant; typically use smaller column L (lower N) at SS and higher L (higher N) at larger scale → safety

factor)

■ Same resin (particle characteristics) and fluid characteristics (conc. etc)

Keep normalized load same across scales:■ gprotein/Lmedia is constant

Increase both column diameter/length, i.e. resin volume, to accommodate larger load keeping Q constant

Benefits- Maximize use of media

- Maximize use of floor space- Greater flexibility for equipment

41

Many issues relate to packing method differences between scales

Issue*: ■ Packing method not sufficient at large scale – led to channeling during

product elution. Resolved by increasing packing flow and decreasing the operating flow rate

Chromatography Scaling – Avoiding Pitfalls

A280 n

m

A280 n

m

A280 n

mA

280 n

m

dc = 7 cm, H = 22 cm, 300 cm/h

dc = 35 cm, H = 22 cm, 300 cm/h

dc = 44 cm, H = 22 cm, 300 cm/hdc = 44 cm, H = 22 cm, 450 cm/h

* S. Aldington, J. Chrom. B 848 (2007), 64-78

42

■ Reliable scale-up of unit operations is a key factor in ensuring the

success of a process operation

■ There is a scientific approach to scale-up

Similarity criteria

Linear, predictive, hybrid

■ There is a practical consideration in scale-up

Facility fit

Equipment constraint at manufacturing scale

■ Successful scale-up of operations uses the right mix of good science

with practical experience!

Summary

Thank You

reliable and predictable scale-up of unit operation in

Documents