Development and validation of a UHPLC–MS/MS method for simultaneous quantitation the plasma concentration of Sabarubicin and its alcohol metabolite M3 in Chinese small cell lung cancer patients

• Built a UHPLC–MS/MS method for simultaneous quantification of Sabarubicin and its alcohol metabolite in human plasma.
• Lower limit of quantitation was 2 ng/mL for Sabarubicin and 0.5 ng/mL for M3 with a sample volume of 100 μL.
• Method was proved to be sufficient for pharmacokinetics study in Chinese SCLC patients.

To support a novel anthracycline agent – Sabarubicin’s pharmacokinetics study in Chinese small cell lung cancer patients, a rapid, sensitive, and high throughput ultra-performance liquid chromatography tandem mass spectrometry method using Doxorubicin hydrochloride as internal standard (IS) was developed and validated for simultaneously quantifying Sabarubicin and its alcohol metabolite M3 in human plasma. Plasma samples were pre-extracted with n-hexane to remove hydrophobic interferences and the target compounds were extracted into a 1 ml mixture of chloroform and isopropanol (1:1, v/v) and separated on an ACQUITY UPLC BEH Shield RP18 (100mm × 2.1 mm, 1.7 μm) column with gradient mobile phase composed of acetonitrile and water containing 0.1% formic acid. Detection was performed by electrospray ionization in the positive ionization mode under multiple reaction monitoring of the transitions at m/z 644 → 130 for Sabarubicin, m/z 646 → 333.2 for M3, and m/z 544 → 360 for IS. For Sabarubicin and M3, calibration curves over 2–400 ng/ml and 0.5–100 ng/ml could achieve excellent linearity respectively(r > 0.99). Intra- and inter-day precisions were 1.5%–9.1% and 2.2%–12.8%, and accuracy were −9.6% to 0.7% and −4.8% to 5.9% for Sabarubicin and M3 respectively at four concentration levels. The mean recovery for Sabarubicin was 62.4%, 71.9% for M3, and 58.8% for IS. This method was completely validated and successfully applied in the pharmacokinetics study of Sabarubicin and M3 in Chinese small cell lung cancer patients.