The formation clearance of the metabolite is the fraction of the drug CL_T that is responsible for the formation of the metabolite. It is the product of the drug CL_T and the fraction of the drug dose converted to the metabolite (f_m).

When all the administered drug dose is metabolized to one metabolite, the formation clearance should be equal to the CL_T of the drug (f_m = 1).

When multiple metabolites are formed by parallel metabolism, each metabolite will have its own formation clearance. The sum of the formation clearances for all metabolites should not be more than the drug CL_T.

The sum of the formation clearances of the metabolites will not be equal to the drug CL_T if the drug elimination involves pathways other than drug metabolism.

The metabolite total body clearance is the volume of the plasma or blood which is completely cleared from the metabolite per unit time. It has units of vloume/time.

The CL_T(m) for the metabolite is constant within a patient (dose and concentration independent) when its elimination processes follow first-order kinetics.

The CL_T(m) is a measure of the efficiency of all eliminating organs in eliminating the metabolite.

The metabolite elimination rate constant and the metabolite half life (the dependent pharmacokinetic parameters) are dependent on (is determined from) the metabolite total body clearance and the metabolite volume of distribution (the independent pharmacokinetic parameters).