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Perfusion Medium Considerations

Case Study: Continuous Perfusion at Varying Medium Concentrations
Most commonly associated with perfusion is a continuous perfusion process. Here the goals are to quickly
achieve and maintain a process at steady-state with
a specific quality profile for a period of time, usually
limited by cell line stability or cell retention fouling
risk. This case study shows steady-state perfusion
operation of the same cell line at two concentrations
of medium.

The bleed was adjusted to actively
target 95% cell viability to mimic
a process with very high product
quality needs.

160

100

140

120
100

90
85
80

80
60
40

CHO K1 66% LGPM VCD
CHO K1 LGPM VCD
66% LGPM % cell viability

20
0

LGPM % cell viability

Days from inoculation

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75
70
65
60

Viability (%)

Viable cell density
(x 10 6/mL)

A cell line was thawed, passaged, and expanded in 0.66X
HIP CHO Medium (faster growth rates were observed
with this clone at low cell density). It was seeded into
two 3 L stirred-tank vessels at 2 L operating fill volume,
again at 0.66X concentration. The continuous perfusion
run was started on day 3 with ATF2 filters at 1 VVD. The
bleed was adjusted to actively target 95% cell viability to
mimic a process with very high product quality needs.
One vessel (in blue in Figures 3-5) continued using
0.66X medium. The other vessel (in red in Figures 3-5)
was perfused using 0.66X and 0.20X medium on days 3

Figure 3. Viable cell
density and percent
viability of continuous
perfusion operating
with two different
concentrations of the
HIP CHO Medium. Fully
concentrated medium
was initially excessively
bled causing an
excessively high percent
viability and lower-thannecessary VCD.

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