Application of a Sensitive Liquid Chromatography-Tandem Mass Spectrometric Method to Pharmacokinetic Study of Telbivudine in Humans

Significance of the Topic

Telbivudine is an antiviral L-nucleoside analogue whose therapeutic monitoring requires precise quantification in human plasma. Sensitive and selective analytical methods support dose optimization and safety assessment in clinical trials.

Objectives and Study Overview

This study aimed to establish and validate a robust LC-MS/MS assay for telbivudine in human plasma, covering a broad dynamic range and ensuring reliability for pharmacokinetic profiling in healthy volunteers.

Methodology and Instrumentation

Sample Preparation:

• Aliquot 100 µL plasma, add 40 µL deuterated internal standard with thymidine phosphorylase, incubate 1 hour at 37 °C in the dark.
• Precipitate proteins with 200 µL acetonitrile, vortex 1 min and centrifuge 5 min at 13 000 rpm.
• Transfer 200 µL supernatant for UHPLC-MS/MS injection (2 µL volume).

Chromatographic and Mass Spectrometric Conditions:

• UHPLC: GL Sciences InertSustain C18 (3.0 mm×100 mm, 2 µm), column at 40 °C, gradient elution (5→80% acetonitrile) at 0.4 mL/min.
• MS/MS: Shimadzu LCMS-8050 triple quadrupole with ESI (positive mode), MRM transitions m/z 243.10→127.10 for telbivudine and 246.10→130.10 for internal standard.

Used Instrumentation

• Shimadzu Nexera UHPLC system (LC-30AD pumps, CTO-30A oven, DGU-30A5 degasser, SIL-30AC autosampler).
• GL Sciences InertSustain C18 column (3.0 mm I.D. × 100 mm, 2 µm).
• Shimadzu LCMS-8050 triple quadrupole mass spectrometer with ESI interface.

Main Results and Discussion

The method exhibited:

• Linear dynamic range 1.0–10 000 ng/mL with r² > 0.9999.
• LLOQ at 1 ng/mL meeting ±15% bias and precision criteria.
• Intra- and inter-day precision ≤ 2.5% RSD at 3, 30 and 8 000 ng/mL.
• Recoveries 100.6 ± 2.5%, 104.5 ± 1.5% and 104.3 ± 1.6% for low, medium and high QC levels.
• Matrix effects normalized by internal standard (99–101.5%).
• Sample stability: 8 h at room temperature, three freeze/thaw cycles at –20 °C, and 72 h in autosampler at 10 °C.

Benefits and Practical Applications

This high-throughput assay provides clinicians and researchers with a reliable tool for pharmacokinetic studies of telbivudine, supporting dose adjustment, therapeutic drug monitoring and drug–drug interaction assessments.

Future Trends and Applications

Advances may include integration with automated sample preparation, microflow LC-MS for reduced solvent use, high-resolution mass spectrometry for metabolite profiling, and multiplexed assays for simultaneous quantification of nucleoside analogues in personalized medicine.

Conclusion

The validated LC-MS/MS method demonstrates excellent sensitivity, precision and robustness, making it well suited for clinical pharmacokinetic investigations of telbivudine in human plasma.