Simultaneous Analysis of Tacrolimus, Sirolimus, Everolimus, and Cyclosporine A in Whole Blood Using an Agilent Ultivo Triple Quadrupole LC/MS

Importance of the Topic

Immunosuppressant drugs such as tacrolimus, sirolimus, everolimus, and cyclosporine A play a critical role in preventing organ rejection and managing autoimmune disorders. Accurate quantification of these compounds in whole blood is essential for therapeutic drug monitoring to ensure patient safety and optimize dosing. The complexity of whole blood matrices and low analyte concentrations necessitate highly sensitive and selective analytical techniques.

Objectives and Study Overview

This study aimed to develop and validate a high-throughput liquid chromatography–tandem mass spectrometry (LC–MS/MS) method on the Agilent Ultivo triple quadrupole system for simultaneous analysis of four immunosuppressants in whole blood. The goals included minimizing sample preparation, achieving rapid analysis, and demonstrating robust performance across clinical concentration ranges.

Methodology

Whole blood samples (500 µL) were spiked with internal standards and precipitated using a protein-precipitation reagent. After centrifugation, the supernatant was directly injected. Chromatographic separation was achieved on a JASEM immunosuppressants analytical column at 60 °C, using a 7.5-minute gradient at 0.9 mL/min and a 20 µL injection volume. Detection was performed in positive ion mode with multiple reaction monitoring (MRM) transitions optimized for each analyte. Calibration employed a seven-level lyophilized blood standards kit, and quality controls were assessed over three days.

Used Instrumentation

• Agilent 1260 Infinity II Binary Pump (G7112B)
• Agilent 1290 Infinity II Vialsampler (G7129B)
• Agilent 1260 Infinity II Multicolumn Thermostat (G7116A)
• Agilent Ultivo Triple Quadrupole LC/MS (G6465B)
• Agilent Jet Stream Ionization Source

Results and Discussion

The method provided baseline separation of four analytes with retention times between 2.97 and 4.06 minutes. Limits of quantitation ranged from 0.16 to 1.54 µg/L. Calibration curves exhibited excellent linearity (R2 > 0.995) except cyclosporine A, which required a quadratic fit. Intra- and interday accuracies were 98–103% with RSDs below 5%, and no significant carryover was detected.

Benefits and Practical Applications

This dilute-and-shoot workflow reduces sample preparation time and supports high-throughput clinical and pharmaceutical laboratories. The assay’s speed and robustness make it suitable for therapeutic drug monitoring, transplant patient management, and quality control in drug development.

Future Trends and Potential Applications

Emerging directions include integrating automation and microfluidics for sample handling, expanding panels to additional immunosuppressants or metabolites, and coupling with high-resolution mass spectrometry for structural elucidation. The method may adapt to point-of-care devices and incorporate AI-driven data processing for real-time monitoring.

Conclusion

A reliable 7.5-minute LC-MS/MS method on the Agilent Ultivo platform has been established for simultaneous quantification of key immunosuppressants in whole blood. The approach delivers high sensitivity, accuracy, and throughput, providing a comprehensive solution for clinical and research applications.