Development and validation of an LC-MS/MS method for quantitative determination of GS87, a novel antineoplastic...

GS87 is a novel, highly specific GSK3 inhibitor, which has shown to induce extensive differentiation of acute myeloid leukemia (AML) cells in early mouse studies and has great potential for therapeutic advancement. This work described the development and validation of an LC-MS/MS method for quantitative determination of GS87 in mouse plasma. In this method, GS87 and T6447952 (a structural analog used as internal standard) were extracted from plasma using hexane as extraction solvent, and separated isocratically on a Waters XTerra^® MS C8 column (2.1 × 50 mm, 3.5 μm) using a mobile phase consisting of acetonitrile and 5.00 mM ammonium formate (35:65, v/v) pumped at a flow rate of 0.200 mL min^-1. Quantitation of GS87 was done by positive electrospray ionization tandem mass spectrometry operated in multiple-reaction-monitoring (MRM) mode. The method has been validated in accordance with the US Food and drug administration guidelines for bioanalytical method validation. It has linear calibration range of 2.50-250 ng mL^-1 with correlation coefficient of >0.999. The intra- and inter- assay accuracy and precision were ≤ ±5 and ≤6%, respectively. The IS normalized recovery of GS87 was 103-106%. The stability studies showed that GS87 was stable under all tested conditions. The method developed has been successfully applied to the measurement of GS87 concentrations in mouse plasma samples from an animal study, and may be useful for further preclinical investigation of GS87.