Clinical Sample Collection

Pharmacokinetics, a branch of pharmacology, is concerned with the determination of the fate of externally administered substances (mostly chemical) to a living organism. By definition and in principle as well, it deals with all kinds of compounds – such as hormones, metabolites, toxins and even nutrients – that are ingested by an organism or delivered to it in external forms. However, in practice the application of this discipline is mainly pharmaceutical, that is, concerned with drug substances.
The discipline describes the body’s affects on a specific drug post-administration – how the drug is acted upon by the biochemicals (enzymes, for example) and the speed of such processes. Thus it is classified into these aspects of drug-body interaction, viz., the extent and rate of Absorption (of substances of drug entering blood circulation), Distribution (of substances through body fluids and tissues), Metabolism (or irreversible transformation of parent compounds into daughter metabolites) and Excretion (of substances from the body). This is popularly termed as the ADME scheme.
Recent developments in the study of drug-body interactions suggest the inclusion of the new term, Liberation (of substances from the drug from the formulation, on entering the body). In view of this, Pharmacokinetics begins to deal with the LADME scheme. For the purpose of study, pharmacokinetics is often combined with pharmacodynamics.