Bioavailability

Bioavailability - The proportion of a drug that reaches the target organs and tissues, usually expressed as a percentage of the dose administered. Intravenous administration results in 100 per cent bioavailability because the drug is injected directly into the bloodstream. Drugs taken orally have a much lower bioavailability. Preparations that have equal bioavailabilities are described as bioequivalent. (See also drug.)