Single-Use Technology

Summary

Disposable technology for freezing protein based drug sub-

stances is a new approach designed to enable short or long

term storage of drug substances in a convenient, cost effec-

tive container. Three case studies focus on the development of freeze-

thaw cycles in disposable bags using cryopreservation systems.

Development starts from the production system, and then scales down

to the lab system for protein assessment. In all three cases, freeze-

thaw cycles were developed for the lab system either to match a prod-

uct-specific production scale temperature trace, or to bracket defined

minimum and maximum production volumes (loads). For a high con-

centration protein study, a model protein was used in cycle develop-

ment in an attempt to eliminate an observed super cooling phenome-

non.

IntroductionFrozen drug substance storage is a conservative and generally

preferred method, when extended storage is needed, due to the bene-

fits of increasing product stability, extending shelf life, and decreas-

ing potential for microbial growth. Drug substance can be frozen,

then thawed and finished according to market demands, or in the case

of clinical drug product, to supply potentially lengthy early clinical

trials. However, freeze-thaw stresses may arise during these process-

es by cold and heat denaturation, by freeze concentration (cryo-con-

centration), and by interaction of solutes with the ice-liquid interface

[1-4]. These stresses may cause precipitation of buffer resulting in pH

shifts [5, 6], concentration of salt to destabilize protein [7], and pro-

tein partial unfolding [8], all of which could lead to activity loss.

Minimizing these stresses to achieve maximum product stability

should be the primary objective when developing a freeze-thaw

process. Additionally, freezing and thawing rates are also important

factors that can impact protein stability and activity, and require atten-

tion to detail in defining the freezing and thawing processes [9, 10].

Freeze-thaw, when coupled with disposable bags, provides

some advantages over the traditional rigid container system including

operational flexibility and a reduction in capital requirements. Frozen

bags can be conveniently stored in a choice of freezers: chest, upright,

and walk-in. A single use bag system can be designed to provide a

shorter freezing distance for a given volume than commercially avail-

able rigid containers, thereby significantly reducing the resistance to

heat transfer [11]. Handling and transport configurations are available

to facilitate shipping. Additionally, pre-sterilized bag systems offer

aseptic connections, and eliminate the need for hard-piped in-house

sterilization then further reducing capital as well as operating and

maintenance costs. Single use systems could virtually eliminate the

risks of cross contamination, particularly in multiple product facili-

ties. The use of disposables combined with freeze-thaw production

technology is therefore gaining attention.

Developing a robust freeze-thaw process to maintain product

stability is essential to product preservation and storage. Unlike

freeze-drying, seemingly little attention is given to the development

of freeze-thaw processes. For freeze-drying scale-up, it is important

to maintain equivalent product temperature profiles or similar prod-

uct ‘thermal history’ [12], and equivalent drying rates [13]. It is

believed that a similar product temperature profile or drying rate

would yield the same product characteristics and consequently the

same product stability.

This principle can be applied to freeze-thaw process scale-up or

scale-down. In a recent publication, P. Shamlou [14] demonstrated

that geometry of the freezing container is a key parameter, and it

could be designed to optimize the freeze-thaw operation by minimiz-

ing cryo-concentration and freeze time. Rectangular container geom-

etry can be manipulated in such a way that the freezing rate is deter-

mined predominantly by one-dimensional heat conduction, or by tem-

perature. Linear scale-up is then based on equivalency of tempera-

1

American Pharmaceutical Review

Development of Freeze andThaw Processes for BulkBiologics in Disposable Bags

Kin Ho, Serguei Tchessalov, Angela Kantor, Nicholas WarneDrug Product Development, Wyeth Biopharma

Ho_APR 7/9/08 3:23 PM Page 1

ture-time profile (equivalency of cryo-concentration). This equivalen-

cy concept should be applied to both freezing and thawing steps.

Considerations for Freeze-Thaw Cycle Development

Programmed parameters including temperature, time and mixing

speed during thawing affect the outcome of the freeze-thaw operation.

During freezing, the set point temperature and processing time yield

the resulting product temperature profile. When performed properly,

mixing during thawing minimizes the effect of cryo-concentration

caused by freezing and promotes a homogeneous product upon thaw.

All of these parameters should be considered in the freeze-thaw devel-

opment plan.

The commercially available system for freeze-thaw of biomate-

rials in disposable bags contains a freeze-thaw module, accommodat-

ing either up to 100L with a 6-bag system at 16.6L each (full produc-

tion scale), or 1 bag system with 16.6L capacity (pilot or smaller pro-

duction scale). The lab scale development system can host up to 10

bags at 30 or 100 mL. Both production and development systems are

designed to have equivalent freezing-thawing distance, as shown in

Figure 1, where the width of the 30 or 100 mL bag is equal to the depth

of the 16.6L bag. With this design, the production and development

scale systems are considered scalable to each other and equivalent

freezing and thawing rates produce equivalent product temperature

profiles.

Due to the size of the production systems for bulk freezing

processes, freeze-thaw rates are inherently slow [1]. Both freezing and

thawing should proceed as fast as the systems can operate to prevent

potential effects such as product deterioration and stability concerns,

and also provide a reasonable batch operating time. The maximum

speed of operation (maximum freeze-thaw rates), regardless of the

handling volume, allows the manufacturing facility to use one standard

recipe to bracket the minimum load (4.2L) and the maximum load

(100L for 6 bag system and 16.6L for 1 bag system). It is preferable in

a commercial manufacturing facility to validate only one recipe for the

entire range of production batches and multiple product operations.

In order to obtain freeze-thaw rates equivalent for production

and development systems, there is a need for the development system

to purposely slow the freeze-thaw process to accommodate a much

smaller handling volume. The set point

temperature profile for the 2 different sys-

tems should be different due to the differ-

ences in scale. A standard recipe for max-

imum freeze-thaw rate is expected to gen-

erate various product temperature profiles

depending on the handling volume. And

two very different product profiles will be

generated for the minimum and maximum loads. Two separate set

point profiles should be developed in the development system to

model the minimum and maximum product profiles at production

scale.

The frozen storage temperature for biologics generally falls in

the range of –80°C to –20°C. The selected storage temperature is ulti-

mately defined by product stability. It is preferable, if possible, to

develop a drug substance formulation stable at –20°C versus –80°C, or

any lower temperature to realize long term energy and equipment cost

savings. Operational logistics for storage and product shipment are

also more favorable at higher frozen temperature.

As previously mentioned, definition of freeze-thaw temperatures

is critical, not only for product stability, but also for disposable con-

tainer integrity. The construction material of disposable plastic bags is

usually a co-extruded material comprised of several layers of film. The

commercially available bags for frozen storage are made with ethylene

vinyl acetate (EVA). EVA has brittleness temperatures at approximate-

ly –70°C and –76°C [15, 16]. Considering that the freezing container

is designed to undergo multiple freeze-thaw cycles, processes in which

the film is exposed at or below stated brittleness temperatures could

potentially compromise the integrity of the bag. An operation where

the drug substance is frozen and stored at –50°C might be reasonable

based on protein product stability and the brittleness temperature of

the plastic film. It is logical for the freezing temperature to be the same

as the storage temperature. Yet, some products may be stored at –20°C

after being frozen at –50°C, if the product is stable at –20°C and the

subsequent annealing would not cause unwanted crystallization, which

could impact product stability. Frozen biologics should be thawed at

the fastest rates determined to maintain product stability by appropri-

ate studies.

Development (Scale-down) StrategyAs mentioned earlier, the goal of scale-up or scale-down is to use

an equivalent temperature and time profile for the target solution,

which is called product temperature trace equivalency. Freeze-thaw

scalability not only depends on the product temperature profile, but

also the geometry of the bags. The geometry of the freezing container

is a key factor that could impact freezing performance (freeze concen-

tration and freeze time).

Our choices for a development approach include: 1) matching

the temperature trace of a production scale run, if appropriate, or 2)

bracketing the production loads with faster and slower freeze-thaw,

both at development scale, thus modeling the minimum and maximum

loads at maximum production operating rates. Depending on the proj-

ect scope and our experience with the protein of interest, different

approaches can be taken. It would take more effort and time to devel-

op a matched trace cycle. In early product development, matching a

production scale trace may be preferred simply because of lack of

experience with the protein. It would also make sense to use the

matching approach for production with a fixed batch size. After gain-

ing more experience later in development and with a more developed

stability profile, a bracketing approach becomes more appealing.

2

American Pharmaceutical Review

Figure 1.

Abbreviations

HTF: heat transfer fluid TC: thermocouple

HMW: high molecular weight species

Same freeze-thaw path length for production and lab scale systems: bag depth of16.6L = bag width of 30 or 100 mL

Ho_APR 7/9/08 3:23 PM Page 2

Case StudiesCase Study #1

There was a need to extend the expiry of a conjugated antibody

drug substance for manufacturing flexibility at a contractor site. One

option was to freeze the drug substance. After considering several

frozen options, the disposable (one bag model) at production scale

was chosen, mainly because the batch size of 30L lent itself to the

16.6L bag configuration, i.e. 2 bags would accommodate the batch.

Stability sensitivity of this conjugate and fixed production batch size

led the development decision to utilize the matching approach.

It is known from previous experience with this conjugate that

freeze-thaw could induce an increased level of unconjugated toxin, an

active ingredient normally stably conjugated to the protein. The pur-

pose of the study was to evaluate the conjugate stability by screening

the appropriate freeze-thaw conditions for this process. We knew that

thawing rates were critical to conjugate stability, and, if not optimal,

could also cause precipitation. We tried 3 different freeze-thaw

cycles: maximum rates at production scale with thawing set points at

25 ° C or 15°C, as well as a control condition to match the 6-bag pro-

duction model rate. The placebo formulation (protein only) was used

as the test solution at production scale to conserve the conjugate

material.

Protein and unconjugated toxin level were assessed using the 3

cycles that were developed in the production scale system and con-

verted to the development system. The maximum thaw rate at 15°C

was selected for production implementation based on the stability

data and precipitation observations (data not shown). Figure 2 shows

an example of a placebo trace at production scale compared to that at

development scale. At both scales, the temperature-time profiles

showed equivalency.

Case Study #2

Currently drug substance of a commercial fusion protein is

stored frozen in stainless steel vessels. Often the drug substance ves-

sel, after dispensing of the required quantity for filling and lyophiliza-

tion, does not contain sufficient volume for re-freeze in another ves-

sel because the quantity is less than the minimum load at 18L. Freeze-

thaw in disposable bags could resolve the issue since the bag size

(16.6L) is appropriate. Residual drug substance from each drug prod-

uct batch can be frozen, and then thawed when enough bags of drug

substance are available to produce a drug product batch. The 6-bag

model was chosen mainly for the required thaw capacity.

Two conditions were investigated at production scale: maxi-

mum total load of 100L (6 bags at 16.6L) and minimum load of 4.2L

with five slots empty. The generated product temperature profiles

were then used as controls to develop the development system freeze-

thaw cycles, using the bracketing method described above. Two cycle

programs were developed in the development scale system: fast

freeze-thaw and slow freeze-thaw. The fast freeze-thaw cycle was

designed to produce cooling and warming rates faster than in a 4.2L

load at production scale, while the slow freeze-thaw cycle can pro-

duce rates slower than those for freezing and thawing of 100L mate-

rial at production scale. Freezing and thawing of a 4.2L volume is

expected to be the fastest of any allowed volume, while freeze-thaw

of a 100L volume is expected to be the slowest process. The cycles in

the development system, which are slower than 100L and faster than

4.2L, should, in principle, cover all possible product temperature pro-

files that can be generated in the production system. Figures 3 and 4

illustrate an example of the cooling/warming product temperature

profile and rate comparison using the 4.2L product temperature pro-

file and the 30mL bag profile for fast freeze-thaw.

Fast freeze-thaw and slow freeze-thaw cycles were performed

using drug substance at 25 mg/mL on the development system to con-

firm the production cycles. These runs reproducibly bracketed the

fastest cycle (single 16.6L bag filled with 4.2L) and slowest cycle (six

16.6L bags) in the production system. No significant effect on protein

quality was observed after the drug substance experienced up to 5x

freeze-thaw cycles using the fast and slow cycle programs.

Additionally, lyophilized drug product prepared from solution that

previously experienced freeze-thaw cycles showed no significant

effect on protein quality (data not shown).

Case Study #3

A high concentration dosage form can provide flexibility in

clinical trials. Treating chronic diseases can require significant quan-

tities of a therapeutic to accommodate large doses over long periods.

High concentration drug product reduces the volume of injections,

and during production it translates to less volume to handle and store.

However, higher protein concentration could easily lead to a higher

level of freeze concentration during freeze-thaw which could lead to

undesired degradation. Minimizing the freezing distance could be an

effective way to avoid the freeze concentration, and the disposable

bag system is a favorable container choice.

This feasibility study was performed for a 150kDa monoclonal

antibody (mAb1) in late stage product development. Currently, drug

substance is stored in stainless steel vessels (minimum load 18L) at

–50°C connected to a commercially available vessel frozen storage

system. Development studies showed that HMW increased upon mul-

tiple freeze-thaw cycles, and the HMW was traced to the presence of

mannitol. The HMW also had a scale effect in the presence of manni

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American Pharmaceutical Review

-60

-40

-20

0

20

40

0 3 6 9 12 15

Time, hour

Tem

peratu

re, °C

HTF Setpoint

TC#4

TC#5

TC#6

TC#7

15°C thaw, placebo,

production

Figure 2.

-70

-60

-50

-40

-30

-20

-10

0

10

20

30

0 1 2 3

Run time, hour

Tem

perature,°C

TC#9, 30mL

TC#10, 30mL

4.2L

-25

-20

-15

-10

-5

0

5

10

15

20

25

30

0 2 4 6 8

Run time, hour

Te

mp

era

tu

re

,°C

TC#9, 30 mL

TC#10, 30 mL

4.2L

Figure 3.

Placebo at 15°C thaw, lab scale traces vs. production trace

Product temperature profile comparison between 4.2L and 30mL bag. Both cooling(A) and warming (B) in 30mL bag were faster than in 4.2L bag.

Ho_APR 7/9/08 3:23 PM Page 3

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American Pharmaceutical Review

tol. When mannitol was present, a reduced process volume main-

tained the HMW level as compared to the maximum load [17]. As a

quick resolution, mannitol was removed from the drug substance for

mulation, and added back during the drug product process.

Several factors drove us to investigate disposable freeze-thaw

technology. These included demands for a high concentration dosage

form, limited availability of the vessel frozen storage system for

future applications, and the desire to refreeze small amounts of drug

substance (<18L). Therefore, a feasibility study was initiated to eval-

uate the freeze-thaw of mAb1 drug substance at high concentration

with and without mannitol. Ultimately the results can be used to rec-

ommend a new drug substance concentration and formulation, as well

as the drug product production process.

The 6-bag model was chosen for mAb1. We decided on the

bracketing approach for freeze-thaw cycle development. With an

approach similar to that of Case Study 2, attempts were made to

develop freeze-thaw cycles. A step of –70°C was included during

freezing for ice nucleation. An unexpected phenomenon, super cool-

ing, was observed in the development system with freeze temperature

depressed (Figure 5). The super cooling event was sporadic and

showed no pattern in frequency of occurrence or bag position. This

phenomenon has not been observed at production scale possibly

because large-scale bags with large solution volume can generally

provide enough nucleation sites for ice formation. In the development

system the super cooling phenomenon was observed in 2 out of 3 tri

als and randomly occurred in protein or buffer runs. The occurrence

of super cooling not only affected the nominal freeze time (5°C to

–5°C) calculation, but it seemed related to protein concentration level.

A higher protein concentration seemed to correlate to a higher level of

uncertainty in super cooling occurrence. The impact of super cooling

during freeze-thaw was unknown. Therefore, a freeze-thaw cycle with

super cooling is definitely not considered a robust cycle. Due to the

limited supply of mAb1, a model protein mAbM was used for cycle

development in the effort to eliminate super cooling.

The mAbM material was prepared at 50, 100 and 150 mg/mL,

and filled into bags. The bags were then frozen and thawed 5 times.

Again, to conserve material, the post multiple freeze-thaw materials

were frozen and thawed 5 more times after mannitol addition.

To eliminate the super cooling, some revisions were made to the

set point program including extending initial deep freezing duration to

15 minutes from 5 minutes, and lowering initial freezing temperature

to facilitate nucleation. This revised program was first tried on buffer

5 times, then tried on the mannitol-free mAbM solutions 5 times, and

finally on the mannitol-containing mAbM solutions. No super cooling

was observed on any of the 15 runs (example in Figure 6). In summa

ry, the super cooling phenomenon was not seen in any of the 15 runs

with protein concentration up to 150 mg/mL, which mimics the mAb1

potential concentration. All runs also showed good reproducibility.

Lastly, the revised set point program was used to evaluate mAb1 sta-

bility. Figure 7 shows the mAb1 and mAbM overlay when using the

revised cycle.

Figure 8 summarizes the stability results of the study. The

mAb1 without mannitol remained stable for up to 5x freeze-thaw

cycles in disposable bags at all tested concentrations. With mAb1 for-

mulations at 50mg/mL containing mannitol, it was observed that

HMW increased with the number of cycles, and faster freeze-thaw

rates seemed to be more favorable to mAb1 stability. As a result of the

study, mAb1 with mannitol at 50mg/mL was not recommended as a

drug substance formulation for frozen storage in disposable bags. At

high concentration with and without mannitol, HMW did not change

-6

-5

-4

-3

-2

-1

0

1

-63 -43 -23 -3

Product temperature,°C

Co

olin

g ra

te

,°C

/m

in

TC#9, 30mL TC#10, 30mL4.2L

-0.5

0

0.5

1

1.5

2

2.5

3

-23 -18 -13 -8 -3

Product temperature,°C

Wa

rm

in

g ra

te

, °C

/m

in TC#9, 30mL

TC#10, 30mL4.2L

Figure 4.

-80

-60

-40

-20

0

20

40

0 3 6 9 12 15

Time, hour

Tem

peratu

re, °C

HTF Setpoint

TC#8

TC#9

TC#10

Figure 5.

-80

-60

-40

-20

0

20

40

0 3 6 9

Time, hour

Te

mp

era

ture

, °C

HTF Setpoint

TC#1, 50

TC#2, 100

TC#3, 150

TC#4, 50

TC#5, 100

TC#6, 150

TC#7, 50

TC#8, 100

TC#9, 150

TC#10, buffer

Production

Figure 6.

Cooling rate (A) and warming rate (B) comparison between 4.2 L and 30mLbag. Both cooling and warming in 30mL bag were faster than in 4.2L bag.

Two out of 10 thermocouple traces showed super cooling

Example of slow freeze cycles: mAbM up to 150 mg/mL with 10 TC traces,with no super cooling

-80

-60

-40

-20

0

20

40

0 5 10 15 20 25

Time, hour

Te

mp

era

ture

, °C

HTF Setpoint

Run 5, TC#4, mAb1

Run 2, TC#6, mAbM

Figure 7.

mAb1 and mAbM temperature trace overlay, no super cooling was observedfor any of the 10 thermocouples up to 10 runs with and without mannitol.

Ho_APR 7/9/08 3:23 PM Page 4

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American Pharmaceutical Review

as a function of freeze-thaw cycle. This finding gave us a feasible long

term resolution to the HMW formation issue. Mannitol-containing

mAb1 when >100mg/mL could be considered as a drug substance for-

mulation with no freeze-thaw stability concerns. Additionally manni-

tol-containing mAb1 drug substance at high concentration can elimi-

nate the addition of mannitol during drug product production, which

saves process time and effort.

Conclusions Freeze-thaw profiles have been successfully developed and

have shown feasibility of freeze-thaw operations with disposables for

all three case studies. The production system is always programmed

to run at its fastest speed for freezing and thawing, which allows for

one generic recipe (set-point profile) regardless of the load size. It is

a preferable practice in commercial manufacturing to utilize and val-

idate only one recipe for the entire range of production batches.

Equivalency of the product temperature profiles between the produc-

tion and development systems were used for scale-up or scale-down.

The same freezing and thawing distances are kept between production

and development scale systems. Depending on the application and sit-

uation, either the matching approach or the bracketing approach can

be chosen for cycle development.

AcknowledgementAuthors would like to thank Andrea Paulson, Matt Olsen and

Liza Rivera for production system experiments.

References1. R. Wisniewski, V. Wu. Chap. 2: Large-scale freezing and thawingof biopharmaceutical products. Biotechnology andBiopharmaceutical Manufacturing, Processing, and Preservation --Drug Manufacturing Technology Series, Vol. 2, Edited by K. Avis, V.Wu. Interpharm Press, Buffalo Grove, IL2. Arakawa, T., S. J. Prestrelski, W. C. Kenney and J. F. Carpenter.

Factors affecting short term and long term stabilities of proteins.(2001) Advanced Drug Delivery Reviews 46 (Mar): 307-3263. P. Privalov. Cold denaturation of proteins. (1990) Crit. Rev.Biochem. Mol. 25(4): 281-3054. D. Greiff, R. Kelly. Cryotolerance of enzymes (1966)Cryobiology, 2: 335-3415. K.A. Pikal-Cleland, N. Rodriguez-Hornedo, G. Amidon. Proteindenaturation during freezing and thawing in phosphate buffer sys-tems: monomeric and tetrameric Beta-Galactosidase. (2000) Arch.Biochem. Biophys. 384(2): 398-4066. B. Chang, C. Randall. Use of subambient thermal analysis tooptimize protein lyophilization (1992) Cryobiology, 29: 632-6567. M. Pikal. Freeze-drying of proteins, Part II: Formulation selec-tion. (1990) Biopharm. 4: 26-308. G.B. Strambini, E. Gabellieri. Proteins in frozen solutions: evi-dence of ice-induced partial unfolding. (1996) Biophys. J. 70(2):971-9769. S. Jiang, S. Nail. Effect of process conditions on recovery of pro-tein activity after freezing and freeze-drying. (1998) Eur. J. Pharm.Biopharmaceut. 45(3): 249-25710. E. Cao, Y. Chen, Z. Cui and P. Foster. Effect of freezing andthawing rates on denaturation of proteins in aqueous solutions.(2003) Biotechnology & Bioengineering 82(6): 684-9011. S. Webb, J. Webb, T. Hughes, D. Sesin, A. Kincaid. Freezing bio-pharmaceuticals using common techniques – and the magnitude ofbulk-scale freeze-concentration. Biopharm (2002) 15(5): 22-3412. S. Tchessalov, D. Dixon, N. Warne. Principles of lyophilizationcycle scale-up. (2007) American Pharm. Review, 10 (2): 88-92 13. S. Tsinontides, P. Rajniak, D. Pham, W. Hunke, J. Placek, S.Reynolds. Freeze drying – principles and practice for successfulscale-up to manufacturing. (2004) Int. J. of Pharmaceutics. 280: 1-1614. P. Shamlou, L. Breen, W. Bell, M. Pollo, B. Thomas. A newscalable freeze-thaw technology for bulk protein solutions. (2007)Biotechnol. Appl. Biochem. 46 (part 1): 13-2515. J. Brydson. Plastics Materials, 7th Edition. (1999) Elsevier16. Overview – Ethylene Vinyl Acetate Copolymer (EVA), Filmgrade. www.matweb.com17. K. Ho, D. Luisi, D. Sek, A. Kantor, N. Warne. Characterizationof cryo freeze-thaw of a monoclonal antibody solution in stainlesssteel: effect of process scale and excipient level. (2005) AAPSAnnual Meeting, Nashville, TN

SummaryFreezing protein based drug substances in disposable bags is a

new approach designed to enable long-term storage of drug sub-

stances in a convenient, disposable container. This study focuses on

the development of a freeze/thaw cycle for a high concentration

antibody in disposable bags using cryopreservation systems.

Development starts from the production system, then scales down to

the lab system for protein assessment. Freeze and thaw cycles were

developed for the lab system to bracket the minimum and maximum

production range using a model protein. Results demonstrate that the

antibody of interest was stable in 2 of the 3 conditions/concentra-

tions tested after multiple freeze and thaw.

Fast F-T

0

2

4

6

8

10

12

0 1 2 3 4 5 6

Cycle

%H

MW

A

Slow F-T

0

2

4

6

8

10

12

0 1 2 3 4 5 6

Cycle

%H

MW

50+man

50-man

100+man

150-man

Linear

(50+man)

B

Figure 8.

Fast (A) and slow (B) freeze-thaw %HMW results.

Ho_APR 7/9/08 3:23 PM Page 5

Kin Ho is a Senior Process Engineer in theDrug Product Development at WyethBiopharma, Andover, MA. She has been withWyeth since 1998. She is responsible for thedevelopment, scale-up, technical transfer andsupport of the drug product manufacturingprocesses for clinical and commercial proteinbased biologics, as well as physical characteri-

zation of these products. Kin’s current interests include sterile fil-tration, freeze and thaw cycle development, as well as scale-down of the production scale stainless steel and disposable Cryosystems.

Angela Kantor is a Principal Research ScientistII in the Formulations and Process Developmentgroup at Wyeth BioPharma. Ms Kantor isresponsible for development of dosage forms fornew antibody and other protein molecules. MsKantor received a Master's degree in Zoologyand Physiology from the University of Wyomingand was at the Dana Farber Cancer Institute,

Collaborative Research, and Seragen prior to joining Wyeth.

Dr. Nick Warne is the Director of theFormulations Group at Wyeth BioPharma inAndover, Massachusetts. He has been at WyethBioPharma for 18 years and has focused on pro-tein stabilization and formulation development.Dr. Warne holds numerous protein formulationpatents and has made several presentations atnational meetings

Dr. Serguei Tchessalov is a Principle ResearchScientist in the Drug Product DevelopmentDepartment, Wyeth BioPharma, Andover, MA. Hehas 25 years experience in lyophilization field.He is responsible for formulation of lyophilizedforms of protein therapeutics, freeze-dryingprocess development, process scale up and manu-

facturing support. His current interests also include the engi-neering aspects of processing of parenteral dosage forms (filtra-tion, filling, freeze-thaw and etc.).

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