A compact microflow liquid chromatography system for at-sample reaction monitoring of pharmaceutical active ingredient synthesis

Process analytical technology (PAT) and real-time release testing (RTRT) are transforming pharmaceutical manufacturing by enabling continuous quality assurance through real-time process data rather than traditional end-product testing. This paper presents Versiti®, a compact microflow liquid chromatography (LC) late-stage prototype system for at-sample deployment, delivering rapid, reproducible separations at the point of sampling. The system was evaluated by adapting an in-process control (IPC) method, originally performed on a benchtop LC system, for monitoring a multi-stage pharmaceutical reaction. Versiti reduced solvent consumption by more than 99% and shortened separation time 4.5-fold, supporting timely process decisions and RTRT principles. To extend applicability to high-concentration reactor streams, the online dilution capability was developed and characterized. By combining dynamic dilution with adjustable injection loop volumes (determined by defined valve rotor configurations), the system achieved dilution factors up to 75 × while maintaining compositional integrity with relative yield variability below 5%. These results position Versiti as a scalable PAT solution aligned with RTRT principles, offering a practical pathway towards automated, sustainable, and near-real-time monitoring in continuous pharmaceutical manufacturing. • A miniaturized LC system enables at-sample monitoring of pharmaceutical reactions. • Achieved > 99% solvent savings and 4.5 × faster separation than conventional HPLC. • Integrated online dilution module delivers highly consistent dilution (up to 75 ×) • Compact, modular design supports sustainable PAT for active ingredient synthesis.