Most variable absorption is seen with which route-

Ans. is 'a' i.e., Oral o Oral administration of drugs is safe, convenient and economical, but has the potential for the most variable absorption pattern. [?][?][?][?][?]Clinical pharmacologyRoutes of drug administrationo Drugs are administered by various routes.o Different routes have different characteristics, so that the route of administration may have a profound effect upon the speed and efficiency with which the drugs act.o The routes of drug administration may be:Local routeSystemic routeo Local route - Drug is administered at the site of lesion.o Systemic route - Drug is administered through systemic routes is intended to be absorbed into the blood stream and distributed all over, including the site of action, through circulation.Routes of drug administrationLocalo Topicalo Intra-articularo Intrathecalo Retrobulbaro Perineuralo Intra-arterialSystemico Oralo Sublingualo Rectalo Cutaneous (Transdermal)o Inhalationo Intranasalo Parenteraly Subcutaneousy Intramusculary Intravenousy IntradermalImportant factso First pass metabolism is seen with oral and rectal routes.o Maximum first pass metabolism is seen with oral route.o In rectal route, drug absorbed into external hemorrhoidal veins bypasses liver, but not that absorbed into internal haemorrhoidal veins - First pass metabolism occurs, but less than oral route (avoids first pass metabolism to 50%).o Most rapid onset of action is seen with I. V. route.o Bioavailability by I.V. route is 100%.