Microsomes and hepatocytes from liver are used to study drug metabolism in vitro. Metabolic transformation of a drug taking place in liver can change significantly its efficacy and safety. For this reason drug candidates are screened early in the discovery process for metabolic stability.
We typically perform metabolic stability assays in mouse, rat and human microsomes or S9 (tests in microsomes from other species or hepatocytes are available upon request). Test compounds are incubated with microsomes supplemented with co-factors at 37°C . Typical conditions are the compound concentration of 2 µM and 5 sampling time-points (0, 5, 10, 20 and 40 minutes), in duplicates. At each time-point, the reactions are terminated by the addition of acetonitrile. The samples are centrifuged, filtered and the parent compound concentration is evaluated by LC-MS/MS measurements (API3000, AB Sciex). This service also includes incubation of the compound with 2 control drugs and a control reaction without co-factors.
Data include parent compound percent remaining, half-life and clearance values. Full study report is provided.
A minimal weighted amount of dry compound, 1 mg, or 200 µL of 10mM stock DMSO solution, is required for this assay. For multiple assays, lesser amount of compound per assay may be sufficient, which should be discussed for each particular case.