Rapid LC-MS/MS Bosutinib Quantification with Applications in Metabolic Stability Estimation.

Area of Science:

• Pharmacokinetics and Drug Metabolism
• Analytical Chemistry
• Oncology Therapeutics

Background:

• Bosutinib (BOS) is an FDA-approved drug for Philadelphia chromosome-positive (Ph+) chronic myelogenous leukemia (CML).
• Accurate quantification of BOS in biological matrices is essential for pharmacokinetic and metabolic studies.
• Existing methods may lack the sensitivity or specificity required for detailed metabolic profiling.

Purpose of the Study:

• To develop and validate a rapid, sensitive, and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for bosutinib (BOS) determination.
• To utilize this method for assessing the metabolic stability of BOS in human liver microsomes.
• To establish a reliable analytical tool for future drug development and pharmacokinetic investigations.

Main Methods:

• A validated LC-MS/MS method using tofacitinib (TOF) as an internal standard.
• Separation achieved on a C18 column with an isocratic mobile phase (acetonitrile-water with formic acid).
• Detection via a triple-quadrupole tandem mass spectrometer (TQD-MS) in positive ion mode.

Main Results:

• The method demonstrated high sensitivity and specificity for BOS quantification in human liver microsomes, with a linear range of 5-200 ng/mL and R² = 0.999.
• Excellent intra- and inter-day accuracy and precision (<4%) were achieved.
• Metabolic stability assessment revealed a high intrinsic clearance (CLint = 34.3 µL/min/mg) and a short in vitro half-life (t1/2 = 20.21 min).

Conclusions:

• The developed LC-MS/MS method is rapid, specific, and reliable for BOS quantification in liver microsomes.
• This method is suitable for metabolic stability evaluations and represents the first LC-MS/MS assay specific for BOS.
• Bosutinib exhibits rapid hepatic elimination, suggesting significant hepatic metabolism and clearance.