(406f) An Integrated PAT Approach for a Lab Scale Bioreactor IgG3 Cell Culture Process Real Time Monitoring: A Feasibility Study

A model mAb IgG3 cell culture process real time monitoring scheme was reported in this work, to explore the possibility of combining real time spectroscopic techniques and off line characterization tools for a bioreactor cell culture process understanding. Both inline NIR and FTIR Spectroscopy were used to monitor various stages of a model mAb IgG3 cell culture process in real time. In-process nutrient composition, Protein A elution profile, and cell size/morphology were determined offline by Nova 100 Bioanalyzer, Protein A Chromatography, and a digitalized light microscopy, respectively. Without inoculating the bioreactor, a two factor full factorial design (agitation rate with 9 levels, sparge rate with 5 levels) were executed in a 7.5L bioreactor to examine if they impact the NIR real time monitoring. The time series of process NIR spectra was subjected to Principal Component Analysis (PCA). A process trajectory was then constructed based on the PCA results. Three-dimension spectral maps of time-wave number-(NIR or FTIR) spectral intensity were constructed. The process trajectory, 3-D spectral maps, and other process and product characterization results were compared to identify significant process events and elucidate process progression dynamics. It was found that within the scope of DOE, the NIR absorbance of the media was insensitive to either agitation rate or sparge rate. However, the pH adjustments during the bioreactor media equilibration process were characterized by a signal singular point and can be accurately tracked by process trajectory. Applying PCA to the cell culture process NIR clearly demonstrated two distinguishable clusters in the sample map, which correlates well with the Protein A elution profile. The 3-D NIR map demonstrated 3 distinguishable process periods: initial decline, stationary, and growth period. The time series of FTIR spectra along with in-process sample microscopy characterization provided further details regarding some characteristics of those periods. Thus, it demonstrated that combining real time process monitoring and bioreactor in-process sample characterization can help to illustrate process progress and map significant process events.