Automated measurement of tacrolimus from hemaPEN dried blood spots using CLAM-203

Significance of the Topic

Micro-sampling with devices like the hemaPEN offers less invasive, cost-effective collection, enabling frequent longitudinal monitoring critical for drugs with narrow therapeutic windows such as tacrolimus.

Objectives and Study Overview

This study demonstrated the integration of dried blood spot (DBS) samples collected via hemaPEN into a fully automated LC/MS/MS workflow. Using the Shimadzu CLAM-2030 module coupled to an LCMS-8060, the method aimed to reliably quantify tacrolimus, a transplant drug with complex pharmacokinetics.

Methodology and Instrumentation

• Sample Collection: hemaPEN and hemaPEN-QC devices provided four 2.74 µL DBS spots per cartridge, dried for at least two hours.
• Automated Extraction (CLAM-2030): filter conditioning with methanol, extraction with 80:20 MeOH/H₂O plus 13C-D2 internal standard, 120 s shaking at 2000 rpm, and 60 s vacuum filtration.
• Chromatography: Nexera X2 UHPLC with phenyl-hexyl trap and analytical columns at 60 °C, isocratic load (90:10 water/MeOH) and elution (90:10 MeOH/3 mM ammonium formate), total run time 1.54 min.
• Mass Spectrometry: LCMS-8060 operated in positive ESI-MRM mode; optimized gas flows and temperatures ensured sensitivity; quantification via stable isotope-labeled internal standard.
• Validation: Following IATDMCT and EMA guidelines, assessed linearity, accuracy, precision, stability, selectivity, recovery, carry-over, matrix, and hematocrit effects.

Main Results and Discussion

• Linearity: 1–100 µg/L with r² > 0.998.
• Accuracy & Precision: Intra- and inter-assay CVs ≤10% (≤20% at LLOQ), accuracies within ±12% (±20% at LLOQ).
• Stability: Tacrolimus stable on DBS for ≥14 days at 4 °C and ≥72 h at 60 °C.
• Recovery & Matrix Effects: Mean recovery ~87%, no significant matrix or hematocrit interferences, no carry-over observed.

Benefits and Practical Applications

• Automated workflow reduces manual labor and errors, accelerating LC/MS/MS data availability.
• Patient-centric sampling enhances comfort and compliance, supporting remote blood sampling.
• Suitable for routine therapeutic drug monitoring in transplant patients requiring frequent tacrolimus measurements.
• Potential healthcare cost savings by minimizing hospital visits and optimizing lab resources.

Future Trends and Potential Applications

• Expanding automated preparation to other solid matrices (e.g., tissue biopsies, multi-analyte DBS panels).
• Integration with point-of-care sampling for decentralized clinical studies.
• Applications in pharmacokinetic research, pediatric dosing, and remote monitoring in resource-limited settings.
• Standardizing micro-sampling workflows for a broader range of biomarkers.

Conclusion

The validated method enables fully automated tacrolimus quantification from hemaPEN-derived DBS using CLAM-2030 and LCMS-8060, delivering high precision, accuracy, and stability for patient-centric therapeutic monitoring.

References

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