Biological half-life

The biological half-life is the length of t ½, in which in a biological organism (human, animal, plant, single-celled organisms ), the content of a substance is dropped exclusively by biological processes ( metabolism, excretion, etc.) by half. For those substances, it may be incorporated, such as the radioactive, toxic or medicinal substances, but also physiologically occurring substances.

In pharmacokinetics is referred to as half-life, the time where the plasma concentration of a drug is decreased to half of the initial value, that is metabolized and / or excreted. It can be composed of several processes which have partially different concentration dependencies.