NVESTIGATING THE IMPLEMENTATION OF CONVERGENCE CHROMATOGRAPHY FOR MEDICINAL CHEMISTRY AND PROCESS DEVELOPMENT LABORATORIES

Importance of the topic

Convergence chromatography integrates multiple separation chemistries—reversed phase, normal phase, HILIC and chiral—on a single platform. In medicinal and process development laboratories this flexibility is crucial to track non-chromophoric impurities, isobaric species and enantiomeric intermediates during complex synthetic sequences. Coupling with mass spectrometry further enhances selectivity and sensitivity, enabling chemists to make informed decisions about reaction progression, yield and purity.

Objectives and Overview

This study examines the implementation of ultraperformance convergence chromatography (UPC2) for reaction monitoring and method development in medicinal chemistry workflows. Key goals include:

• Evaluating UPC2 selectivity compared to high- and low-pH reversed-phase LC (RPLC).
• Demonstrating detection of non-chromophoric and isobaric compounds in rosuvastatin and clopidogrel synthesis steps.
• Screening chiral columns for enantiomeric separations in process development.

Methodology and Instrumentation

Reactions were sampled at defined time points and analyzed by both UPC2 and UPLC with PDA detection. Mass confirmation used an SQD2 single quadrupole detector. Mobile phase A was CO₂; modifier B was 15 mM ammonium formate with 1% formic acid. Key instrument parameters included:

• ACQUITY UPC2 system with six‐column capacity
• PDA and SQD2 detectors
• Column temperatures: 35 °C for chiral, 50 °C for achiral
• Flow rate: 2.0 mL/min; ABPR: 1885 psi
• MassLynx CDS with OpenLynx and OA Login

Main Results and Discussion

In the seventh step of rosuvastatin synthesis, UPC2 resolved isobaric impurities (m/z 362 Da) that coeluted in RPLC, and detected a non-chromophoric reduction impurity at m/z 304 Da. UPC2 peak shape and resolution of starting materials (SM1, SM2) and product were superior to both high- and low-pH RPLC. Chiral screening of clopidogrel intermediates showed that Chiralpak IB provided baseline separation of enantiomers, while Chiralpak ID did not. Mass spectrometry confirmed peak identities and monitored reaction kinetics.

Practical Benefits and Applications

UPC2’s stationary-phase-agnostic design allows rapid switching among separation modes without reconfiguring diluents or hardware. This streamlines reaction monitoring, accelerates troubleshooting of low yields or impurities, and guides purification strategy. Orthogonal selectivity to RPLC reduces method development time and increases confidence in enantiomeric purity assessments.

Future Trends and Opportunities

Advances may include automated UPC2–MS workflows, integration with chemometric and machine-learning tools for real-time reaction optimization, and expanded application to high-throughput screening of both achiral and chiral separations. Column management systems with independent temperature control will further extend column lifetime and method robustness.

Conclusion

Convergence chromatography on UPC2 coupled with mass spectrometry delivers a versatile, orthogonal approach to reaction monitoring in medicinal chemistry. It outperforms conventional RPLC in resolving non-chromophoric, isobaric and enantiomeric species, enabling more efficient synthetic development and purification decisions.

References

Jones MD, McCarthy SM, McKearin J, Kremsky J, Aubin A, Hong P, Maziarz M. Investigating the implementation of convergence chromatography for medicinal chemistry and process development laboratories. Waters Corporation Poster, 2013.