Some new factors have to be taken into account when considering the pharmacokinetics of blood concentration-time curves of substances absorbed through the gastrointestinal tract. These are: 1) the amount of substance which can be absorbed varies with gastrointestinal filling and emptying; 2) invasion into the circulation often does not obey the laws of simple concentration gradients; 3) the interposition of organs of active metabolism such as the liver or intestinal mucosa can lead to a partial or complete change in the substance absorbed; 4) counter-regulatory influences may affect substances absorbed in the gastrointestinal tract, particularly foodstuffs.
KeywordsAscorbic Acid Absorptive Capacity Intestinal Segment Gastrointestinal Absorption Lymphatic Transport
Unable to display preview. Download preview PDF.