Rapid, Sensitive and Direct Quantitation of Tiotropium at sub-pg/mL in Plasma using Shimadzu LCMS-8060

Importance of the Topic

Chronic obstructive pulmonary disease (COPD) management relies on precise measurement of inhaled therapies in plasma to support dose selection and safety monitoring. Tiotropium, a long-acting anticholinergic, exhibits very low systemic bioavailability, necessitating a bioanalytical assay at sub-picogram per milliliter sensitivity. Achieving reliable quantification at 0.2 pg/mL addresses critical regulatory and research needs for low-dose inhalation products.

Study Objectives and Overview

The primary aim was to develop and validate a rapid, robust LC-MS/MS method for direct quantitation of tiotropium in human plasma with a lower limit of quantification (LLOQ) of 0.2 pg/mL. The method supports regulatory compliance and high sample throughput in clinical pharmacokinetic and toxicokinetic studies.

Methodology and Instrumentation

Sample Preparation:

• Plasma volume: 450 µL spiked with tiotropium-D3 internal standard and buffer.
• SPE cleanup: C18 cartridges conditioned, samples loaded, washed (water, 5% methanol), eluted with 50% methanol.

Chromatography and MS:

• Instrument: Shimadzu Nexera X2 UHPLC coupled to LCMS-8060.
• Column: Shim-pack Velox C18 100×2.1 mm, 2.7 µm.
• Mobile phase: 0.1% formic acid in water (A) and acetonitrile (B) at 80:20 (v/v).
• Flow rate: 0.2 mL/min; oven temperature: 50 °C; injection: 40 µL; run time: 7 min; retention time: 5.4 min.
• Ionization: Heated ESI positive mode with UF-Qarray ion guide.
• MRM transitions: Tiotropium m/z 391.95→152.05; Tiotropium-D3 m/z 395.00→155.20 and 173.10 (summed).

Main Results and Discussion

Calibration and Linearity:

• Range: 0.20–200.00 pg/mL; r2 > 0.99; LLOQ signal-to-noise > 20:1.

Accuracy and Precision:

• Intra- and inter-day precision ≤ 15% RSD (≤ 20% at LLOQ); accuracy within ±15% (±20% at LLOQ).

Recovery and Matrix Effects:

• Mean recovery: 57.6% ± 4.99%; matrix factor (IS-normalized) ~0.86 at LQC/HQC.

Stability:

• No significant degradation over bench-top (6 h), autosampler (30 h) or freeze–thaw cycles.

Benefits and Practical Applications

• High sensitivity enables reliable detection at sub-pg/mL levels in low-dose inhalation studies.
• Single-step SPE reduces sample prep time and solvent use, extending instrument uptime.
• Low plasma requirement conserves precious clinical samples and reduces costs.
• Validated per US guidelines, suitable for regulatory submission.

Future Trends and Opportunities

Emerging directions include integration of automated micro-extraction workflows, high-resolution MS for enhanced selectivity, multiplex assays for simultaneous quantitation of multiple inhaled drugs, and application of machine learning for data review and assay optimization. Miniaturized sampling devices and dried blood spot technologies may further reduce sample volume and processing time.

Conclusion

The developed LCMS-8060 method combines low-volume sample extraction, selective SPE cleanup and sensitive MRM detection to achieve a 0.2 pg/mL LLOQ for tiotropium in plasma. Validation results demonstrate excellent accuracy, precision and stability, providing a robust tool for clinical pharmacokinetic and regulatory studies.

References

1. DrugBank: Tiotropium (DB01409), accessed Jan 2020.
2. Wikipedia: Tiotropium bromide, accessed Jan 2020.
3. RxList: Spiriva drug description, accessed Jan 2020.
4. Wang et al., Rapid Commun. Mass Spectrom. 21(11), 2007, pp. 1755–1758.
5. ISSX Intl. Poster 35910, accessed Jan 2020.