Testing robustness: Immunosuppressant drugs in blood with a TSQ Quantis MS for clinical research

Importance of the Topic

Immunosuppressant drugs require accurate quantitation in clinical research to balance efficacy and safety. Mass spectrometry offers the sensitivity and specificity needed for measuring compounds such as tacrolimus, sirolimus, everolimus, and cyclosporin A in whole blood. A robust analytical platform reduces downtime and enhances throughput for routine studies.

Study Objectives and Overview

This investigation assessed the performance and robustness of the Thermo Scientific TSQ Quantis triple quadrupole mass spectrometer in analyzing immunosuppressants over five consecutive days, processing more than 1,500 injections without maintenance. The goal was to confirm precision, accuracy, and stability under a high-throughput workflow.

Methodology

• Sample Preparation: Blood samples, calibrators, and controls were precipitated with ZnSO4/methanol containing internal standards (cyclosporin D, ascomycin), vortexed, refrigerated, centrifuged, and injected directly.
• Liquid Chromatography: Separation used a Vanquish Flex HPLC with a Hypersil GOLD C8 column at 80 °C. Mobile phases were 10 mM ammonium formate with 0.1 % formic acid in water (A) and methanol (B), with a 3-minute runtime.
• Mass Spectrometry: A TSQ Quantis equipped with heated electrospray ionization monitored ammoniated adducts via two SRM transitions per analyte and one per internal standard. Surrogate ions tracked cleanliness.
• Robustness Testing: Daily sequences comprised eight calibrators, repeated sets of five controls, and 20 blank samples. Each ~300-injection sequence was repeated for five days.
• Data Analysis: TraceFinder software was used for quantitation and ion ratio confirmation.

Main Results and Discussion

• Linearity: All analytes displayed linear calibration over 2–60 ng/mL (tacrolimus, sirolimus, everolimus) and 25–1,800 ng/mL (cyclosporin A), with back-calculations within ±20 % over five days.
• Precision: Internal standards showed 4 % and 8 % RSD over 1,500 injections. Control precisions ranged from 2.36 % to 4.22 % RSD for the four drugs (n = 60 injections each).
• Instrument Stability: No phospholipid buildup or signal drift was observed, and no maintenance was required throughout the study.

Practical Benefits of the Method

This workflow delivers rapid (3-minute) and reliable quantitation of key immunosuppressants with minimal sample cleanup. The robust performance of the TSQ Quantis supports high-throughput clinical research without frequent maintenance interruptions.

Future Trends and Potential Applications

Advances may include shorter chromatographic runs, automated sample preparation, and multiplex panels for additional biomarkers. Integration with advanced data processing and high-throughput automation will further support personalized medicine and therapeutic drug monitoring.

Conclusion

The TSQ Quantis triple quadrupole MS demonstrated excellent robustness, precision, and accuracy for immunosuppressant analysis in whole blood, enabling reliable, high-throughput quantitation in clinical research settings.

References

• Technical Note 64969. Thermo Fisher Scientific (2017). Testing robustness: Immunosuppressant drugs in blood with a TSQ Quantis MS for clinical research.