The Use of PATROL UPLC Process Analysis System for Continuous Flow Chemistry Processes in a Pharmaceutical Company

Significance of the topic

Continuous flow chemistry is increasingly adopted in pharmaceutical manufacturing for its superior throughput, yield, scalability, temperature control, and safety compared to batch processes. Real-time analytical techniques are essential to maintain consistent product quality and minimize waste. While spectroscopic Process Analytical Technology (PAT) offers noninvasive, real‐time monitoring, it lacks selectivity and quantitative accuracy for intermediates and low‐level impurities. The integration of UPLC‐based PAT fills this gap, enabling fast, sensitive, and quantitative process insights.

Study objectives and overview

This application note describes the deployment of a PATROL UPLC Process Analysis System for at‐line monitoring of a continuous flow reaction that produces 160 kg of a pharmaceutical intermediate. The study aimed to reduce analysis cycle times, support a design of experiments (DoE) on reactant stoichiometry and flow rates, and enable rapid process adjustments at both lab‐scale and large‐scale laboratories.

Methodology and instrumentation

A DoE was conducted varying the flow rates and molar equivalents of two starting materials (RM1 and RM2) around their center points. An existing HPLC method (6 min run) was translated to a 2.2 min UPLC assay using an ACQUITY UPLC C18 column (2.1×30 mm, 1.7 µm), gradient elution with water, acetonitrile, and 1 % TFA, at 60 °C column temperature and 15 °C sample temperature. A 1 µL injection and 1.4 mL/min flow provided chromatographic‐quality separations. Multi‐point calibration curves for reactants (0.13–2.5 mg/mL) and product (1.23–1.75 mg/mL) were generated in Empower 3 software. Automated dilution workflows were implemented via the Process Sample Manager.

Used instrumentation

• PATROL UPLC Process Analysis System
• Empower 3 Chromatography Data Software
• ACQUITY UPLC C18 column (2.1×30 mm, 1.7 µm)
• Process Sample Manager for automated sample dilution

Main results and discussion

The UPLC method reduced laboratory analysis time from 6 min to 2 min, facilitating rapid DoE screening. Key findings included optimal yield at center‐point flow rates, increased impurities when RM1 flow exceeded center point relative to RM2, and yield decline at the highest RM1 flow. On scale‐up in the large‐scale laboratory, at‐line sampling and automated dilution enabled a full analysis cycle in 3 min versus 10 min by traditional HPLC. This speed allowed timely detection of an unexpected reaction color change and adjustments to reagent flows, cutting potential product loss from an estimated 5 kg to 1.5 kg.

Benefits and practical applications

• Threefold reduction in analysis cycle time supports high‐throughput continuous flow operations
• Quantitative, selective monitoring of reactants, product, and impurities in near real time
• Enhanced process understanding drives rapid optimization and smoother scale‐up
• Complementary to spectroscopic PAT, offering sensitivity to low‐level impurities

Future trends and potential applications

Integration of UPLC‐based PAT with automated flow platforms and advanced data analytics will pave the way for predictive, self‐optimizing manufacturing. Emerging microfluidic sampling, AI‐driven data interpretation, and inline robotics will further minimize manual intervention and enable UPLC PAT deployment in multistep flow syntheses.

Conclusion

The PATROL UPLC Process Analysis System has proven to be a powerful tool for real‐time, quantitative monitoring of rapid continuous flow reactions. By delivering high sensitivity and fast cycle times, it empowers process chemists to make informed decisions, minimize material losses, and maintain consistent product quality throughout development and scale‐up.