LC-MS/MS Method for the Determination of Paclitaxel in Human Serum

Importance of the topic

Paclitaxel is a critical chemotherapeutic agent widely used in treating ovarian, breast, head and neck cancers, and Kaposi’s sarcoma. Accurate quantification of paclitaxel in human serum at low concentrations supports therapeutic drug monitoring, pharmacokinetic studies, and quality control in clinical and research laboratories.

Study objectives and overview

This application note describes the development of a rapid, sensitive LC-MS/MS method to determine paclitaxel levels in human serum. The approach employs Thermo Scientific SOLA solid phase extraction (SPE) products for sample cleanup and Accucore RP-MS HPLC columns for fast chromatographic separation, achieving a 2 minute cycle time without compromising peak shape or reproducibility.

Methodology and Used Instrumentation

The workflow combines SPE clean-up, chromatographic separation, and tandem mass spectrometric detection:

• Sample preparation: Human serum samples spiked with paclitaxel and docetaxel (internal standard) are pretreated, loaded onto SOLA 10 mg/2 mL SPE cartridges, washed, and eluted with acetonitrile/ammonia. Eluates are dried under nitrogen and reconstituted in aqueous/acetonitrile with sodium acetate to promote stable sodium adduct formation.
• Chromatography: Separation is performed on an Accucore RP-MS 2.6 µm, 50 × 2.1 mm column using a 60–70% methanol gradient in 2 minutes at 0.6 mL/min, 30 °C.
• Mass spectrometry: A TSQ Vantage triple quadrupole with heated electrospray ionization in positive mode monitors selected reaction monitoring (SRM) transitions (paclitaxel m/z 876.3 → 308.3; docetaxel m/z 830.3 → 549.2).

Main results and discussion

The method demonstrates linearity from 0.1 to 10 ng/mL (r2 = 0.9982). The lower limit of quantitation (LLOQ) at 0.1 ng/mL shows clear, well-shaped chromatographic peaks. Precision evaluated at QC levels of 0.3, 1.5, and 6 ng/mL yields %CV ≤ 6.6%. Recovery assessed by post-extraction overspikes at 0.75 ng/mL averages 116%. Back-calculated standard accuracies across the range are within ±10%.

Benefits and practical applications

This streamlined protocol offers:

• High sensitivity for low-level paclitaxel detection enabling robust pharmacokinetic profiling.
• Reproducible recoveries and precision suited for routine clinical and bioanalytical labs.
• Minimal solvent consumption and rapid processing ideal for high-throughput workflows.

Future trends and possibilities

Emerging trends include integrating microflow LC to reduce solvent use further, exploring automated SPE platforms for higher sample throughput, and expanding the method to multiplexed assays of additional anticancer drugs. Advances in high-resolution mass spectrometry could also enhance selectivity and enable simultaneous metabolite profiling.

Conclusion

The presented LC-MS/MS method utilizing SOLA SPE and Accucore RP-MS columns provides a fast, sensitive, and reliable assay for quantifying paclitaxel in human serum. It meets stringent criteria for linearity, precision, and recovery, supporting diverse bioanalytical applications in oncology research and therapeutic monitoring.

References

• None specified in source document.