Quantitation of Immunosuppressant Drugs in Whole Blood Using the Prelude- SPLC System and TSQ Endura Mass Spectrometer for Research

Importance of the Topic

Immunosuppressant drugs such as cyclosporine A, tacrolimus, sirolimus, and everolimus require precise measurement at therapeutic levels to guide dosing and prevent graft rejection in transplant research and clinical studies.

Aims and Overview of the Study

This work describes the development of a rapid, sensitive, and selective LC-MS/MS method that quantifies four key immunosuppressants in whole blood using an integrated online sample cleanup and chromatography platform.

Methodology and Instrumentation

Sample Preparation:

• Aliquots of whole blood (200 µL) were protein-precipitated with zinc sulfate and methanol containing isotopically labeled internal standards (D12-cyclosporine A, 13CD2-tacrolimus).
• After vortexing and centrifugation, 40 µL of supernatant was injected directly into the system.

Liquid Chromatography:

• Online cleanup on a Cyclone-P TurboFlow column (0.5×50 mm) using the Thermo Scientific Prelude SPLC system with TurboFlow technology.
• Chromatographic separation on an Accucore C8 column (3×30 mm, 2.6 µm) maintained at 70 °C; total run time 5 minutes and solvent consumption 8.1 mL per sample.
• Dual-channel multiplexing enabled up to 576 injections per 24 hours.

Mass Spectrometry:

• Detection on a Thermo Scientific TSQ Endura triple quadrupole mass spectrometer equipped with heated electrospray ionization.
• Selected-reaction monitoring transitions optimized for each analyte and internal standard.
• Data acquisition and processing using Thermo Scientific TraceFinder software v3.1.

Main Results and Discussion

Calibration and Linearity:

• All four calibration curves exhibited excellent linearity (R2 > 0.994) across therapeutic concentration ranges.

Accuracy and Precision:

• Quality control samples fell within ±20% of nominal values, meeting research accuracy criteria.
• Representative chromatograms showed sharp peaks and reproducible retention times within a 1.75-minute detection window.

Comparative Analysis:

• Measured drug concentrations in donor samples correlated closely with immunoassay data, demonstrating method validity.

Benefits and Practical Applications

• Automated online cleanup reduces manual handling, streamlining sample preparation and minimizing potential errors.
• Dual-channel operation maximizes instrument utilization and throughput for high-volume research laboratories.
• Stable retention times, enhanced peak shape, and low solvent usage improve cost-effectiveness.

Future Trends and Opportunities

Future directions in bioanalytical chemistry include further miniaturization of workflows, integration of multiplexed sample processing, and the adoption of real-time data analytics. Extending online extraction techniques to broader drug panels and metabolomics, along with the application of high-resolution mass spectrometry and machine learning–driven data review, will enhance selectivity, sensitivity, and throughput.

Conclusion

The optimized LC-MS/MS method using the Prelude SPLC system and TSQ Endura spectrometer delivers rapid, accurate, and reproducible quantitation of four immunosuppressant drugs in whole blood. Automated online cleanup, short cycle times, and multiplexed operation substantially increase laboratory efficiency while upholding rigorous analytical performance.

References

• Yu B, DiBussolo J, Van Natta K, Kozak M. Quantitation of Immunosuppressant Drugs in Whole Blood Using the Prelude-SPLC System and TSQ Endura Mass Spectrometer. Thermo Fisher Scientific Application Note 604, 2016.