100 % bioavailiability is seen with which route

Ans. (b) IntravenousRef Katzung Pharmacology 10th ed. Ch 3* Bioavailability is defined as the fraction of unchanged drug reaching the systemic circulation following administration by any route.In case a drug is give orally, the bioavailiablity shall be less than 100%. This is due to# Incomplete extent of absorbtion# First pass metabolismRoutes of Administration, Bioavailability, and General CharacteristicsRoute of AdministrationGeneral characteristicsBioavailiabiltyIntravenousOnset of action is fastest100%IntramuscularPainful75-100%SubcutaneousLesser volumes can be given compared to intramuscular route75-100%Per oralMost convenient from patients perspective5% to <100%First pass metabolism limits blood levelsPer rectalLess first pass metabolism than peroral30 to <100%TransdermalVery slow absorbtion Lack of first pass effect Prolonged duration of action80-100%