Online/at‐line measurement, analysis and control of product titer and critical product quality attributes (CQAs) during process development

Process analytical technology (PAT) has been defined by the Food and Drug Administration as a system for designing, analyzing, and controlling manufacturing through timely measurements to ensure final product quality. Based on quality‐by‐design (QbD) principles, real‐time or near‐real‐time data monitoring is essential for timely control of critical quality attributes (CQAs) to keep the process in a state of control. To facilitate next‐generation continuous bioprocessing, deployment of PAT tools for real‐time monitoring is integral for process understanding and control. Real‐time monitoring and control of CQAs are essential to keep the process within the design space and align with the guiding principles of QbD. The contents of this manuscript are pertinent to the online/at‐line monitoring of upstream titer and downstream product quality with timely process control. We demonstrated that an ultra‐performance liquid chromatography (UPLC) system interfaced with a UPLC‐process sample manager (UPLC‐PSM) can be utilized to measure titer and CQAs directly from bioreactors and downstream unit operations, respectively. We established online titer measurements from fed‐batch and perfusion‐based alternating tangential flow bioreactors as well as product quality assessments of downstream operations for real‐time peak collection. This integrated, fully automated system for online data monitoring with feedback control is designed to achieve desired product quality. The PAT tools we described in this paper highlights the online capability of UPLC‐PSM system for measuring upstream product titer and downstream product quality, providing the option to facilitate timely process control to achieve desired product quality. With the current deficit in PAT tools for QbD enabled bio‐pharmaceutical processes, these tools will be quite valuable, especially in the emerging field of QbD based continuous bioprocessing.