4.6. Measurement of Plasma Stability

The plasma stability assay was performed by incubation of human or rat plasma with a test compound in a final concentration of 1 μM for 120 min at 37 °C. The incubation was terminated by addition of 40 μL of ice-cold acetonitrile and vortexing for 5 min. The precipitated proteins were removed by centrifugation at 14,000× g for 5 min at 4 °C. Aliquots of the supernatant were injected onto a Shimadzu Nexera XR LC system. Percentages of the parent compound remaining were calculated by comparing peak areas using the Xcalibur software (version 1.6.1, Waltham, MA, USA).