Metabolic stability assay in liver microsomes

Aim: Screening of in vitro metabolic stability of test compound in pooled human and preclinical species liver microsomes.

Background information: Metabolism is the enzymatic modification of drugs to enable their excretion. Although metabolites are typically inactive, some metabolites may be pharmacologically active.

The liver is the main site of drug metabolism in the body. Liver microsomes are subcellular fractions which contain membrane bound drug metabolising enzymes, such as cytochromes P450 (CYP). CYPs are involved in the metabolism of most drugs in clinical use.

Metabolic stability is assessed by measuring test compound depletion with time under linear conditions. Results can be used to assess interspecies differences in metabolism and in vitro intrinsic clearance, which in turn, can be used to predict in vivo hepatic clearance.

Compound requirement: 50 µl of 10 mM DMSO solution

Turnaround time: 1 week / 15 compounds / 3 species

Experimental design:

  • Test compound concentration: 1 µM (variable on request)
  • Number of replicates: 1
  • Final organic solvent: 1%
  • CYP concentration: 0.3 nmol/ml
  • Cofactor: NADPH
  • Time points: 0, 10, 20, 40 and 60 min
  • Control: positive control with known stability
  • Stability in incubation media run in parallel
  • Analytical method: UPLC-MS/MS

Delivered results

  • In vitro half-life
  • In vitro intrinsic clearance

% test compound remaining at each time point relative to time 0