Chemical Stability Testing of Daraxonrasib Using Ultrashort 2.1 x 10 mm UPLC Columns

Significance of the topic

Daraxonrasib is an investigational oncology candidate whose chemical stability under physiologically relevant conditions is essential to interpret downstream in vitro and in vivo studies. Rapid, high-throughput in vitro stability screening reduces time and cost in early drug discovery and prevents confounding by rapid chemical degradation. Ultrashort UPLC columns (2.1 x 10 mm) combined with tandem quadrupole MS offer a practical approach to increase time resolution of stability measurements while lowering solvent and energy consumption compared with conventional 30–50 mm columns.

Objectives and overview of the study

The study aimed to evaluate whether an ultrashort 2.1 x 10 mm UPLC column coupled to a Xevo TQ-S micro tandem quadrupole MS can (1) provide sufficiently selective and reproducible data to monitor chemical stability and (2) increase sampling frequency to better characterize degradation kinetics. Two compounds were examined: Omeprazole (positive control known to degrade in acid) and Daraxonrasib (test compound). Each was monitored under acidic (0.1 N HCl), neutral (PBS), and basic (0.01 N NaOH) conditions at 37 °C over 27 hours.

Methodology

• Sample preparation: 10 mM stocks in 60:40 water:acetonitrile. Final test concentration 100 µM in the respective catalyst; samples prepared in triplicate and loaded into QuanRecovery 96-well plates. A neat 100 µM standard and blanks were included.
• Chromatography: ACQUITY Premier Binary Solvent Manager with Column Manager and PDA. Column: XSelect HSS T3, 2.1 x 10 mm, 2.5 µm. Column temp 30 °C; sample temp 37 °C; injection volume 1.0 µL; flow 0.5 mL/min.
• Mobile phases: A = water + 0.1% formic acid; B = acetonitrile + 0.1% formic acid. Gradient: 5% B hold 0.15 min, linear to 100% B in 0.26 min, hold 0.06 min, return and re-equilibrate 0.66 min. Total cycle 1.25 min per injection.
• Mass spectrometry: Xevo TQ-S micro, ESI positive, MRM detection. Capillary 3.00 kV; cone 30 V; desolvation 350 °C with 1000 L/hr; cone gas 10 L/hr. MRM transitions were confirmed for Omeprazole and optimized (two transitions) for Daraxonrasib.
• Data management: MassLynx software. Timepoints: 0, 15, 30, 45 minutes, 1 hour, then hourly up to 27 hours, enabling high temporal density of measurements.

Instrumentation used

• ACQUITY Premier LC System (Binary Solvent Manager with Column Manager and PDA detector)
• Xevo TQ-S micro Triple Quadrupole Mass Spectrometer (ESI+, MRM)
• XSelect HSS T3 Column, 2.1 x 10 mm, 2.5 µm
• QuanRecovery 96-well plates and MaxPeak 700 µL vials/plates
• MassLynx chromatography data system

Main results and discussion

• Omeprazole: As expected, Omeprazole exhibited rapid degradation under acidic conditions with significant loss of peak area within 15 minutes and continued decrease over 27 hours. In PBS (neutral), Omeprazole showed a gradual decline (<50% loss over 27 h). In basic conditions (0.01 N NaOH) it remained largely stable across the test period. The neat standard (no catalyst) showed no temperature-induced loss, confirming chemical catalyst-driven degradation.
• Daraxonrasib: Across acid, neutral, and basic conditions at 37 °C, Daraxonrasib demonstrated stable peak areas over the full 27-hour experiment. Peak areas were higher in the acidic solutions than in neutral or basic media; the authors attribute this to possible adduct formation or pH-dependent ionization differences rather than time-dependent degradation. The stability observed supports progression of Daraxonrasib into more extensive metabolic or stability profiling experiments.
• Method performance: The ultrashort column provided a 1.25-minute cycle time per injection, enabling ~12 injections per 15 minutes and >1,000 injections over 24 hours. This high throughput increased temporal resolution for detecting rapid degradation events and allowed dense time-series monitoring that would be impractical with longer columns (e.g., a scaled 50 mm method estimated at ~6.25 min per injection).

Benefits and practical applications of the method

• Substantially reduced analysis time and increased timepoint density, enhancing characterization of fast degradation kinetics in DMPK and early discovery stability screens.
• Reduced solvent and energy consumption relative to longer columns, improving analytical greenness and lowering consumable costs and waste.
• Compatibility with selective tandem quadrupole MS facilitates targeted monitoring of known analytes in complex matrices, where full chromatographic resolution is not required.
• Enables screening of more candidates or higher-resolution kinetic studies without sacrificing selectivity provided by MRM detection.

Future trends and potential applications

• Broader adoption of ultrashort columns for high-throughput DMPK and stability screening, particularly when coupled to sensitive and selective MS detectors.
• Integration with automated sample handling and microplate workflows to further increase throughput for large compound libraries and to support time-resolved degradation studies.
• Method miniaturization and greener workflows: further reduction in solvent usage and energy through optimized gradients and lower system dwell volumes.
• Combining ultrashort separations with orthogonal detectors (e.g., high-resolution or ion-mobility MS) for cases where fast separations need to be paired with structural elucidation of degradants.

Conclusion

Ultrashort 2.1 x 10 mm UPLC columns coupled to a tandem quadrupole MS provide a pragmatic balance between speed and selectivity for early-stage chemical stability testing. The approach successfully detected rapid degradation of Omeprazole under acid stress and demonstrated that Daraxonrasib remains chemically stable across acidic, neutral, and basic conditions over 27 hours. The method's high cycle rate, reduced solvent use, and compatibility with MRM detection make it attractive for high-throughput DMPK workflows and rapid stability screening.

References

1. Kerns E. High-Throughput Physicochemical Profiling for Drug Discovery. J. Pharm. Sci. 2001;90(11):1838–1858.
2. Kerns E., Di L. Pharmaceutical Profiling in Drug Discovery. Drug Discov Today. 2003;8(7):316–323.
3. Hughes JP, Rees JP, Kalindjian SB, Philpott KL. Principles of Early Drug Discovery. Br. J. Pharmacol. 2010;162:1239–1249.
4. The Role of in vitro Testing in Drug Development. Pion Blog. Accessed 30-Jul-2026.
5. De Nardi C., Bonelli F. Moving from Fast to Ballistic Gradient in LC-MS/MS Pharmaceutical Bioanalysis: Matrix Effect and Chromatographic Evaluations. Rapid Commun. Mass Spectrom. 2006;20(18):2709–2716.
6. Dunn-Meynell K., Wainhaus S., Korfmacher W. Optimizing an Ultrafast Generic HPLC-MS/MS Method for Faster Discovery PK Sample Throughput. Rapid Commun. Mass Spectrom. 2005;30:2905–2910.
7. Tanna N., Plummer C., Walter TH. Improved Bioanalytical Performance Using a Simplified 2-Step Oasis PRiME HLB Protocol with an Ultra-Short UPLC Column for UPLC-MS/MS. Waters Application Note. September 2025.
8. Berthelette K., Collins C., Walter TH. Improving Throughput and Analytical Greenness in Pharmaceutical Discovery Using Ultrashort (2.1 x 10 mm) HPLC Columns. Waters Application Note. October 2025.
9. Cregg J., et al. Discovery of Daraxonrasib (RMC-6236), A Potent and Orally Bioavailable RAS(ON) Multiselective, Noncovalent Tri-complex Inhibitor. J. Med. Chem. 2025;68(6):6064–6083.
10. El-Badry M., Taha E., Alanazi F., Alsarra I. Study of Omeprazole Stability in Aqueous Solution: Influence of Cyclodextrins. J Drug Deliv Sci Technol. 2009;19(5):347–351.