Development of an analytical method to determine E7130 concentration in mouse plasma by micro-sampling using...

E7130 is a novel microtubule inhibitor and a promising tumor microenvironment ameliorator. Since the amount of the administration in preclinical study is very small due to the high potency of E7130, this study aimed to establish a sensitive analytical method to measure E7130 concentration in mouse plasma samples obtained via microsampling. A sensitive and validated method was developed based on ultra-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-HRMS). Chromatographic separation was achieved using a Waters ACQUITY UPLC BEH C18 1.7 µm (2.1 × 50 mm) column. Mobile phase A comprised 0.1% formic acid and 10 mM ammonium formate in water, and mobile phase B was methanol. A gradient elution was applied at a flow rate of 0.5 mL/min. The calibration curve drawn was linear in the 0.2-100 ng/mL E7130 concentration range for mouse plasma microsamples (10 µL). Analytical results demonstrated good precision (<6.7%) and accuracy (88.5%-100.0%) in E7130 quantitation, indicating that UHPLC-HRMS is a useful method for pharmacokinetic analysis and a valuable approach for the quantitation of hardly fragmented compounds.