Bioavailability

Part of speech: noun

Definitions

1. The fraction of a substance that becomes available in the bloodstream after administration, impacting its efficacy in treatments
2. A metric indicating the speed and extent to which an active ingredient is absorbed by the body and utilized by tissues
3. The proportion of a compound that enters circulation upon administration, influencing its therapeutic effectiveness and overall utilization within the body

Etymology: Bioavailability is a modern technical coinage, built from two parts that are both much older. The first, "bio-", comes from the Ancient Greek "bíos", meaning "life", and reached English as a combining form used to build terms about living things. The second part, "availability", is the ordinary English noun from "available", meaning something that can be obtained or used. Put together, the term describes how much of a substance can actually reach the living system it is meant to affect. The application is what gives the word its precision. In pharmacology, a drug taken by mouth may be only partly absorbed into the bloodstream, so the fraction that does arrive is the "available" part, and the term measures that fraction. The Greek ancestor of the first element never imagined pills or bloodstreams, so the meaning here is entirely a product of modern science.

Synonyms: availability, accessibility