In pharmacology, bioavailability is a subcategory of absorption and is the fraction of an administered dose of unchanged drug that reaches the systemic circulation, one of the principal pharmacokinetic properties of drugs. When a medication is administered intravenously, its bioavailability is 100%. However, when a medication is administered via other routes, its bioavailability generally decreases or may vary from patient to patient. Bioavailability is one of the essential tools in pharmacokinetics, as bioavailability must be considered when calculating dosages for non-intravenous routes of administration.
· Absolute bioavailability
· Relative bioavailability and bioequivalence
· Factors influencing bioavailability