<prompt> 100 Bioavailability is seen with this route:OralIntravenousIntramuscularSubcutaneous  <response>: Bioavailability is fraction of unchanged drug reaching the systemic circulation following administration by any route.IV route has 100 bioavailability.Routes of administration, bioavailability, and general characteristicsRouteBioavailability CharacteristicsIntravenous IV100 by definitionMost rapid onsetIntramuscular IM75 to 100Large volumes often feasible; may be painfulSubcutaneous SC75 to 100Smaller volumes than IM; may be painfulOral PO5 to 100Most convenient; first-pass effect may be importantRectal PR30 to 100Less first-pass effect than oralInhalation5 to 100Often very rapid onsetTransdermal80 to 100Usually very slow absorption; used for lack of first-pass effect; prolonged duration of action 