Improving a High Sensitivity Assay for the Quantification of Teriparatide in Human Plasma Using the ionKey/MS System

Importance of the Topic

Human plasma levels of teriparatide require quantification at low picogram concentrations to support pharmacokinetic studies, therapeutic monitoring, and drug development in osteoporosis treatments.

Objectives and Overview of the Study

The study aimed to transfer a previously developed high sensitivity LC-MS/MS assay for teriparatide to the Waters ionKey/MS System and further enhance sensitivity, reduce sample and solvent consumption, and improve assay performance.

Methodology and Instrumentation

Sample Preparation:

• Protein precipitation with basic acetonitrile to minimize non-specific binding and maintain peptide solubility
• Solid-phase extraction on Oasis HLB 96-well microelution plates for cleanup, concentration, and enhanced selectivity

Chromatography and MS:

• Waters ACQUITY UPLC M-Class system with trap-and-backflush and ionKey™ Source
• iKey Peptide BEH C18 Separation Device (150 μm × 50 mm, 1.7 μm) at 2.0 μL/min and 75 °C
• Xevo® TQ-S triple quadrupole MS in positive ESI mode monitoring teriparatide (m/z 687.05→787.26, 6+ charge state) and rhPTH(1-38) internal standard (m/z 637.58→712.61, 7+)
• Data processed with MassLynx 4.1 and TargetLynx

Key Results and Discussion

• LOD of 10 pg/mL achieved using 200 μL plasma and 10 μL injection, linear range 10–3000 pg/mL (r²>0.99)
• QC accuracy 101–105%, precision CV<5.1% across 25–500 pg/mL levels, meeting FDA criteria
• High m/z y-ion fragments selected to reduce background and improve specificity
• Phase II proof of concept reduced sample to 50 μL and injection to 7.5 μL while boosting S:N ~4× (45:1 vs 11:1 at 20 pg/mL)

Advantages and Practical Applications

• High sensitivity near clinical concentration levels
• Lower solvent and sample use reduces cost and preserves specimens
• Automation-friendly 96-well μElution format and microfluidic chromatography
• Adaptable to peptide and protein bioanalysis in PK, clinical, and QA/QC settings

Future Trends and Applications

Further integration of microfluidic UPLC-MS platforms and advanced data analytics will enable even lower detection limits and multiplexed analyses. Expansion to additional therapeutic peptides, biomarkers, and complex biologics will support precision medicine and streamlined drug development workflows.

Conclusion

The adapted ionKey/MS assay delivers robust and sensitive teriparatide quantification in human plasma with reduced sample and solvent consumption, meeting regulatory standards and offering enhanced throughput for peptide bioanalysis.

References

• Eli Lilly and Company Teriparatide (Forteo) US package insert, 2009.
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• Bansal S DeStefano A AAPS J. 2007;9:E109–114.