(log ppb) HPRT VF (x 10

Metabolism Studies:
Liver in vitro metabolism systems
Summary
� Liver in vitro metabolism systems exist at different levels and applicabilies,
including studies on metabolic stability, metabolic profiling, enzyme induction/
inhibition and drug-drug interaction
� Limitations: Liver in vitro systems may not provide an overall picture of the
metabolism due to the contribution of other organs and tissues and due to the
lack of enzymes and/or cofactors in the respective system
� For incorporating metabolism into in vitro endpoint tests, the charactersitics of
the test compounds and the test systems have to be taken into account, since most
likely predictivites of „black box tests“ may be low