A half life of a substance is the amount of time it takes to decay into half of its activity. Usually, this refers to the body's getting rid of a substance. This happens by the function of kidneys and liver as well as excretion.
Biological Half-life Media
Time course of drug plasma concentrations over 96 hours following oral administrations every 24 hours (τ). Absorption half-life 1 h, elimination half-life 12 h.