Biomedical Engineering Reference
In-Depth Information
Fig. 18
Lot genealogy for batch 25 of the UF/DF step
Fig. 19
Lot genealogy for batch 26 of the UF/DF step
4.1 Case Study 1: Root Cause Investigation
4.1.1 Problem Statement
Company A has a process monitoring program in place that mandates it to perform
periodic process reviews. During one such review it was observed on a run control
chart that the final protein yield for the Ultrafiltration/ Diafiltration (UF/DF) step
for two batches (batch 25 and batch 26) was unusually lower than for other
batches, as shown in Fig.
17
. Since these batches met all batch release criteria,
these observations went unnoticed during regular batch release activity.
4.1.2 Investigation
Tracing the lot genealogy (Figs.
18
and
19
) for batches 25 and 26, the related
batches that fed these outlier batches in the UF/DF step were investigated.
Trends for various parameters in these steps involving these related batches
were investigated, and it was observed that PF-Batch 15 and PF-Batch 17 at the
fermentation step had abnormal titre at harvest (Fig.
20
) and slower cell growth
profiles (Fig.
21
) compared with other batches.
Going back to the lot genealogy (Figs.
18
and
19
), it was observed that a
common batch SF-Batch 35 (at the seed fermentation stage) fed both the abnormal
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