**4.3 Metabolite profiling**

At dose levels greater than 100 mg/kg, the primary clearance mechanism is typically saturated resulting in greater interaction between the drug entity and other P450 enzymes. Metabolite profiling analyses typically use blood samples collected at tox level doses greater than 100 mg/kg; ideally samples at or near the Cmax. The metabolites are typically identified early during the lead optimization stage in the soft spot/metabolite identification studies. The parent and metabolites are typically quantitated via LC–MS/MS methods. The end goal is to obtain the percent abundance of each metabolite relative to the parent.
