MEDICAL PHYSIOLOGY

Detailed explanation-1: -Regardless of the route of administration, drugs must be in solution to be absorbed. Thus, solid forms (eg, tablets) must be able to disintegrate and deaggregate. Sometimes various globular proteins embedded in the matrix function as receptors and help transport molecules across the membrane.

Detailed explanation-2: -For these reasons, most drugs are absorbed primarily in the small intestine, and acids, despite their ability as un-ionized drugs to readily cross membranes, are absorbed faster in the intestine than in the stomach (for review, see [ 1.

Detailed explanation-3: -Absorption can be accomplished by administering the drug in a variety of different ways (e.g. orally, rectally, intra-muscularly, subcutaneously, inhalation, topically, etc.). Note, that if a drug is administered intravenously (placed directly into the blood stream), the need for absorption is bypassed entirely.