3.6 Process Performance and Product Quality of AEX Run with
Quaternary Ammonium Salt
As there is typically a tradeoff between full-rAAV enhancement and rAAV
genome (full capsid) recovery in AEX chromatography, the effectiveness
of TEA-Ac was assessed by plotting the percentage of full-rAAV
(determined by AUC assay) in the AEX elution pool as a function of the
AEX-step genome recovery (calculated based on genome copy determined by
qPCR) for a total of 8 runs. As shown in Figure 5 , two linear
regressions were generated corresponding to either TEA-Ac containing
runs (R2=0.75) or non-TEA-Ac containing runs
(R2=0.79), respectively. The slopes of the two
regression lines are similar, indicating that the tradeoff rate between
full-rAAV percentage to genome
recovery is TEA-Ac independent. However, the intercepts of the two
regression lines are quite different, projecting TEA-Ac containing runs
has ~50% more genome yield than that of non-TEA-Ac
containing runs under same full-rAAV percentage. Taken together, TEA-Ac
demonstrated its effectiveness in AEX preparative process operation
through not only better chromatographic peak separation, but also
enhanced process performance and product quality, holding the promise
for future implementation in scale-up AEX operation.