An Automated Sampling System for Online Monitoring as a Process Analytical Technology (PAT) Tool

Significance of the Topic

The development of real-time, automated analytical methods for bioprocess monitoring is essential to ensure consistent product quality and streamline biotherapeutic manufacturing. Integrating automated sampling with advanced chromatographic techniques provides immediate feedback on critical quality attributes (CQAs), aligning with regulatory Quality by Design (QbD) and Process Analytical Technology (PAT) initiatives.

Objectives and Overview of the Study

• Demonstrate an automated UHPLC-based PAT tool combining Agilent 1290 Infinity II 2D-LC with the Flownamics Seg-Flow sampling system.
• Enable online measurement of multiple CQAs (titer, size variants, charge variants, amino acid concentration) from upstream bioreactor samples using a single setup.
• Reduce analysis time and cost during biotherapeutics development while improving process control.

Methodology and Instrumentation

The study uses a two-dimensional LC approach where a protein A affinity column in the first dimension captures monoclonal antibodies (mAbs), and subsequent second-dimension separations analyze size variants by SEC, charge variants by WCX/SCX, and amino acid concentrations via in-loop OPA/FMOC derivatization.

Instrumentation

• Agilent 1290 Infinity II 2D-LC system: high-speed pumps, multisampler with cooler, multicolumn thermostats, diode array detectors, fluorescence detector, valve drives with heart-cutting and flow-splitting capability.
• Flownamics Seg-Flow automated sampling system with FISP probe for sterile, cell-free bioreactor sampling.
• Software: Agilent ChemStation with 2D-LC module and Flownamics FlowWeb for scheduling and OPC-enabled feedback control.

Main Results and Discussion

• High-resolution heart-cutting and 1:10 flow-splitting reduced second-dimension run time by tenfold, enabling a single injection for multiple CQAs.
• Protein A first-dimension provided real-time titer data; diverted fraction was directed to SEC to quantify monomer and high-molecular-weight species.
• WCX and SCX separations resolved acidic and basic charge variants across multiple fractions.
• In-loop OPA/FMOC derivatization and FLD detection allowed automated online amino acid profiling throughout the bioreactor cycle.

Benefits and Practical Applications

• Simultaneous online monitoring of titer, size/charge variants, and amino acids enhances process understanding and decision-making.
• Significant reduction in analysis time and labor compared to traditional offline assays.
• Real-time integration with distributed control systems (DCS/SCADA) enables proactive feedback control consistent with PAT and QbD principles.

Future Trends and Potential Applications

• Extension to other chromatographic modalities: RP-HPLC, HIC, HILIC, affinity chromatography, reduced/nonreduced denaturing SEC.
• Incorporation of multivariate data analysis (PCA, PLS) for predictive process control and deeper data interpretation.
• Integration of inline spectroscopic sensors (Raman, NIR, FTIR) with 2D-LC outputs for comprehensive real-time analytics.
• Advancement toward fully closed-loop control strategies using OPC-enabled SCADA and enhanced scheduling software.

Conclusion

The Agilent 1290 Infinity II 2D-LC system interfaced with Flownamics Seg-Flow provides a powerful, fully automated platform for online assessment of multiple bioprocess CQAs. By combining affinity capture, heart-cutting or split-flow with SEC, ion exchange, and amino acid derivatization, the approach delivers rapid, reliable data that drive efficient process development and robust quality control in biopharmaceutical production.

Reference

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