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The phases of clinical research are the stages in which scientists conduct experiments with a health intervention to obtain sufficient evidence for a process considered effective as a medical treatment. [1] For drug development, the clinical phases start with testing for drug safety in a few human subjects, then expand to many study ...
The plateau principle is a mathematical model or scientific law originally developed to explain the time course of drug action (pharmacokinetics). [1] The principle has wide applicability in pharmacology, physiology, nutrition, biochemistry, and system dynamics.
Beta phase: A phase of gradual decrease in plasma concentration after the alpha phase. The decrease is primarily attributed to drug elimination, that is, metabolism and excretion. [10] Additional phases (gamma, delta, etc.) are sometimes seen. [11] A drug's characteristics make a clear distinction between tissues with high and low blood flow.
Drug metabolism is the metabolic breakdown of drugs by living organisms, usually through specialized enzymatic systems. More generally, xenobiotic metabolism (from the Greek xenos "stranger" and biotic "related to living beings") is the set of metabolic pathways that modify the chemical structure of xenobiotics, which are compounds foreign to an organism's normal biochemistry, such as any drug ...
The action of drugs on the human body (or any other organism's body) is called pharmacodynamics, and the body's response to drugs is called pharmacokinetics. The drugs that enter an individual tend to stimulate certain receptors, ion channels, act on enzymes or transport proteins. As a result, they cause the human body to react in a specific way.
Identical drugs can produce different results depending on the route of administration. For example, some drugs are not significantly absorbed into the bloodstream from the gastrointestinal tract and their action after enteral administration is therefore different from that after parenteral administration.
If a drug is administered in a form that is not rapidly dissolved, the drug will be absorbed more gradually over time and its action will have a longer duration. A consequence of this is that patients will comply more closely to a prescribed course of treatment, if the medication does not have to be taken as frequently.
A mechanism of action usually includes mention of the specific molecular targets to which the drug binds, such as an enzyme or receptor. [3] Receptor sites have specific affinities for drugs based on the chemical structure of the drug, as well as the specific action that occurs there.