Amlodipine in Human Plasma Using SOLA CX and Accucore RP-MS Column

Importance of the Topic

Amlodipine is an essential antihypertensive agent requiring sensitive and reliable bioanalytical methods to measure low nanogram levels in human plasma. Accurate quantitation supports pharmacokinetic studies and clinical monitoring.

Objectives and Study Overview

This application note describes the development of a rapid, reproducible solid phase extraction procedure using Thermo Scientific SOLA CX 96-well plates combined with ultra-fast liquid chromatography coupled to tandem mass spectrometry on a TSQ Vantage instrument. The goal was to efficiently extract and quantify amlodipine in human plasma within a 3.5-minute run time.

Methodology

Plasma samples were spiked with internal standard nifedipine and calibration standards of amlodipine ranging from 2 to 100 ng/mL. Extraction was performed on SOLA CX plates using methanol and formic acid conditioning, sample loading, sequential water/formic acid and water/methanol washes, and elution with methanol containing 5% ammonia. Eluates were evaporated under nitrogen and reconstituted in methanol for analysis.
Chromatography employed an Accucore RP-MS column (50×2.1 mm, 2.6 µm) with a water/methanol gradient (0.1% formic acid) at 0.35 mL/min and 40 °C. Mass spectrometry used heated electrospray ionization in positive mode, monitoring transitions m/z 409.3→238.1 for amlodipine and 347.1→254.1 for nifedipine.

Instrumentation

• SOLA CX 96-well plates (10 mg, Thermo Scientific)
• Thermo Scientific Accela 600 HPLC system with open autosampler
• Accucore RP-MS analytical column (50×2.1 mm, 2.6 µm) and guard column
• Thermo Scientific TSQ Vantage triple quadrupole mass spectrometer

Main Results and Discussion

The method exhibited linearity across 2–100 ng/mL (r² = 0.991). Quality control samples at 30 ng/mL demonstrated precision (RSD) below 6.9% and accuracy between 97.0% and 113.7%. Chromatographic separation was achieved in 3.5 minutes with high peak efficiency and minimal matrix interference.

Benefits and Practical Applications

• Accelerated sample preparation and analysis suitable for high-throughput bioanalysis
• Reduced solvent consumption and drying times, lowering operational costs
• High reproducibility and extract cleanliness, ensuring data reliability
• Effective removal of endogenous interferences for robust quantitation

Future Trends and Application Potential

Future developments may include expanding SOLA CX technology to additional drug classes, integrating automated SPE platforms, and exploring new core-shell column chemistries for even shorter run times. Advances in miniaturization, green solvent systems, and high-resolution mass spectrometry could further enhance throughput and sensitivity in clinical and pharmacokinetic research.

Conclusion

The combination of SOLA CX solid phase extraction and Accucore RP-MS LC-MS/MS provides a fast, accurate, and reproducible assay for amlodipine in human plasma. This workflow supports efficient pharmacokinetic profiling and routine clinical bioanalysis.

References

1. Stangier J, Su CA. Pharmacokinetics of repeated oral doses of amlodipine and amlodipine plus telmisartan in healthy volunteers. J Clin Pharmacol. 2000;40(12):1347–1354.
2. Drugs.com. Amlodipine drug information. Accessed October 4, 2011.
3. DrugBank. DrugBank entry DB00381: Amlodipine. Accessed October 4, 2011.