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ABSORPTION

المؤلف:  Max M. Houck، Jay A. Siegel

المصدر:  Fundamentals of Forensic Science

الجزء والصفحة:  p356-357

2026-08-10

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ABSORPTION

Drugs may be introduced into a body by a number of means. These include oral, intramuscular, intravenous, rectal, topical, subcutaneous, and inhalation. Different methods are used for different drugs and there is usually a preferred method for a given drug. All methods involve the passage of the drug through a tissue barrier such as stomach or intestine, nasal passages, skin, etc. The chemical nature of the drug dictates how easily the drug can cross the barrier. In addition, the form of the drug can affect its rate of absorption. For example, some drugs including aspirin, for example, may be coated with a substance that slows down absorption so that the drug is gradually absorbed over time. This prevents side effects that may occur if a dose of a drug is suddenly introduced into the body. Once the barrier has been breached the drug will enter the bloodstream. Although a drug may be distributed locally by diffusion through tissues, global distribution through the body is accomplished by way of the bloodstream. When a drug is taken orally it is generally absorbed through the stomach and/or small intestine into the bloodstream. The rate of absorption will depend in part upon what else is already in the stomach at the time of ingestion.