Simultaneous Determination of Osimertinib and its Metabolites in Human Plasma for Clinical Applications Using High-Performance Liquid Chromatography-Tandem Mass Spectrometry.

BACKGROUND

Osimertinib, the first-line treatment for nonsmall cell lung cancer, has 2 main active metabolites, AZ5104 and AZ7550, which demonstrate potency against wild-type epidermal growth factor receptor mutations. In this study, a simple and sensitive analytical method using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/mass spectrometry) was developed and validated to simultaneously quantify osimertinib and its active metabolites in human plasma.

METHODS

Plasma samples were subjected to protein precipitation with zinc sulfate solution and acetonitrile using osimertinib- 13 C, d 3 as an internal standard. The separation was performed on a ThermoScientific Hypersil GOLD C18 column (4.6 × 50 mm, 5 μm) with a mobile phase composed of 0.1% formic acid water-acetonitrile through gradient elution. The compounds were monitored using electrospray ionization in the positive mode with multiple reaction monitoring.

RESULTS

Excellent linearity of calibration curves was observed over the ranges of 10-1000 ng·mL -1 for osimertinib, and 1.5-120 ng·mL -1 for AZ7550 and AZ5104 in human plasma. Both within-run and between-run accuracies were within ±15%, with the coefficient of variation <15%.

CONCLUSIONS

The method met all the validation criteria and was successfully applied to clinical samples from patients with nonsmall cell lung cancer. Furthermore, the correlation between steady-state trough concentrations of osimertinib, AZ5104, and AZ7550 and patients' baseline characteristics were explored. Women exhibited a significantly higher C min, ss for AZ7550 ( P = 0.023). In addition, body mass index was associated with the C min, ss of both AZ5104 ( P = 0.047) and AZ7550 ( P = 0.001).