Time-course of a chemical in a living organism, i.e., increase or decrease of substance at site of measurement due to transport or due to formation or breakdown. The term "toxicokinetics" is also often used synonymously.

Source: AA. VV., Toxicity Testing for Human Health Risk Assessment, in Risk Assessment of Chemicals, 2007, 227-280, DOI: 10.1007/978-1-4020-6102-8_6