Uplc tqd ms

Standard stock solutions of neratinib and IS (sorafenib) were all prepared in DMSO at the concentration of 10 and 2 mg/mL, respectively. When used, stock solutions were diluted with mixed solvent of DMSO and methanol (1:4, v/v) to the desired concentrations as working solutions. 100 µL aliquot of rat plasma (blank or containing neratinib and IS) was mixed with 1.5 mL of methyl tert-butyl ether containing IS (sorafenib, 150 ng/mL) and extracted by vortex for 2 min. After centrifugation at 5000 g for15 min (4°C), the upper organic portion was transferred to a clean tube and dried using SP Genevac Ltd.'s miVac Centrifugal Vacuum Concentrator (Warminster, England). Finally, the residue was reconstituted to 150 µL using acetonitrile/water (50:50, v/v). After centrifugation (12,000 g, 15 min), the supernatant was subjected to UPLC-TQD/MS (Waters) for analyses.