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Context-sensitive Half-life
Context-sensitive half-life or context sensitive half-time is defined as the time taken for blood plasma concentration of a drug to decline by one half after an infusion designed to maintain a steady state (i.e. a constant plasma concentration) has been stopped. The "context" is the duration of infusion. When a drug which has a multicompartmental pharmacokinetic model is given by intravenous infusion it initially will distribute to the central compartment and then move out of this compartment into one or two peripheral compartments. Once this infusion is discontinued, drug continues to move into the peripheral compartments until an equilibrium is reached. At this time, the only way drug may leave plasma is by metabolism or excretion. As the plasma concentration falls, the concentration gradient of drug reverses and drug moves from peripheral compartments back into plasma, maintaining the plasma concentration of the drug, often prolonging the pharmacological effect. If an i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood Plasma
Blood plasma is a light amber-colored liquid component of blood in which blood cells are absent, but contains proteins and other constituents of whole blood in suspension. It makes up about 55% of the body's total blood volume. It is the intravascular part of extracellular fluid (all body fluid outside cells). It is mostly water (up to 95% by volume), and contains important dissolved proteins (6–8%; e.g., serum albumins, globulins, and fibrinogen), glucose, clotting factors, electrolytes (, , , , , etc.), hormones, carbon dioxide (plasma being the main medium for excretory product transportation), and oxygen. It plays a vital role in an intravascular osmotic effect that keeps electrolyte concentration balanced and protects the body from infection and other blood-related disorders. Blood plasma is separated from the blood by spinning a vessel of fresh blood containing an anticoagulant in a centrifuge until the blood cells fall to the bottom of the tube. The blood plasm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steady State
In systems theory, a system or a process is in a steady state if the variables (called state variables) which define the behavior of the system or the process are unchanging in time. In continuous time, this means that for those properties ''p'' of the system, the partial derivative with respect to time is zero and remains so: : \frac = 0 \quad \text t. In discrete time, it means that the first difference of each property is zero and remains so: :p_t-p_=0 \quad \text t. The concept of a steady state has relevance in many fields, in particular thermodynamics, economics, and engineering. If a system is in a steady state, then the recently observed behavior of the system will continue into the future. In stochastic systems, the probabilities that various states will be repeated will remain constant. See for example Linear difference equation#Conversion to homogeneous form for the derivation of the steady state. In many systems, a steady state is not achieved until some time afte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pharmacokinetic
Pharmacokinetics (from Ancient Greek ''pharmakon'' "drug" and ''kinetikos'' "moving, putting in motion"; see chemical kinetics), sometimes abbreviated as PK, is a branch of pharmacology dedicated to determining the fate of substances administered to a living organism. The substances of interest include any chemical xenobiotic such as: pharmaceutical drugs, pesticides, food additives, cosmetics, etc. It attempts to analyze chemical metabolism and to discover the fate of a chemical from the moment that it is administered up to the point at which it is completely eliminated from the body. Pharmacokinetics is the study of how an organism affects a drug, whereas pharmacodynamics (PD) is the study of how the drug affects the organism. Both together influence dosing, benefit, and adverse effects, as seen in PK/PD models. Overview Pharmacokinetics describes how the body affects a specific xenobiotic/chemical after administration through the mechanisms of absorption and distribution ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intravenous
Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrients for those who cannot, or will not—due to reduced mental states or otherwise—consume food or water by mouth. It may also be used to administer medications or other medical therapy such as blood products or electrolytes to correct electrolyte imbalances. Attempts at providing intravenous therapy have been recorded as early as the 1400s, but the practice did not become widespread until the 1900s after the development of techniques for safe, effective use. The intravenous route is the fastest way to deliver medications and fluid replacement throughout the body as they are introduced directly into the circulatory system and thus quickly distributed. For this reason, the intravenous route of administration is also used for the consumptio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infusion
Infusion is the process of extracting chemical compounds or flavors from plant material in a solvent such as water, oil or alcohol, by allowing the material to remain suspended in the solvent over time (a process often called steeping). An infusion is also the name for the resultant liquid. The process of infusion is distinct from both decoction—a method of extraction involving boiling the plant material—and percolation, in which water is passed through the material (as in a coffeemaker). History The first recorded use of essential oils was in the 10th or 11th century by the Persian polymath Avicenna, possibly in '' The Canon of Medicine''. Tea is far older than this, dating back to the 10th century BC as the earliest recorded reference. Preparation techniques Infusion is a chemical process that uses botanicals (typically dried herbs, flowers or berries) that are volatile and release their active ingredients readily in water, oil, or alcohol. In this process, a liqu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Donnan Equilibrium
Donnan can refer to: * Donnan (surname) * Donnan, Iowa, a community in the United States * Donnán of Eigg, Gaelic priest of the 7th century * Donnan equilibrium ** Donnan potential {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metabolism
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the conversion of food to building blocks for proteins, lipids, nucleic acids, and some carbohydrates; and the elimination of metabolic wastes. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. The word metabolism can also refer to the sum of all chemical reactions that occur in living organisms, including digestion and the transportation of substances into and between different cells, in which case the above described set of reactions within the cells is called intermediary (or intermediate) metabolism. Metabolic reactions may be categorized as '' catabolic'' – the ''breaking down'' of compounds (for example, of glucose to pyruvate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Excretion
Excretion is a process in which metabolic waste is eliminated from an organism. In vertebrates this is primarily carried out by the lungs, kidneys, and skin. This is in contrast with secretion, where the substance may have specific tasks after leaving the cell. Excretion is an essential process in all forms of life. For example, in mammals, urine is expelled through the urethra, which is part of the excretory system. In unicellular organisms, waste products are discharged directly through the surface of the cell. During life activities such as cellular respiration, several chemical reactions take place in the body. These are known as metabolism. These chemical reactions produce waste products such as carbon dioxide, water, salts, urea and uric acid. Accumulation of these wastes beyond a level inside the body is harmful to the body. The excretory organs remove these wastes. This process of removal of metabolic waste from the body is known as excretion. Green plants produ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concentration Gradient
Molecular diffusion, often simply called diffusion, is the thermal motion of all (liquid or gas) particles at temperatures above absolute zero. The rate of this movement is a function of temperature, viscosity of the fluid and the size (mass) of the particles. Diffusion explains the net flux of molecules from a region of higher concentration to one of lower concentration. Once the concentrations are equal the molecules continue to move, but since there is no concentration gradient the process of molecular diffusion has ceased and is instead governed by the process of self-diffusion, originating from the random motion of the molecules. The result of diffusion is a gradual mixing of material such that the distribution of molecules is uniform. Since the molecules are still in motion, but an equilibrium has been established, the result of molecular diffusion is called a "dynamic equilibrium". In a phase with uniform temperature, absent external net forces acting on the particles, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terminal Plasma Half-life
Terminal may refer to: Computing Hardware * Terminal (electronics), a device for joining electrical circuits together * Terminal (telecommunication), a device communicating over a line * Computer terminal, a set of primary input and output devices for a computer * Feedback terminal, a physical device used collect anonymous feedback Software * Terminal emulator, a program that emulates a computer terminal within some other display architecture ** Terminal (macOS), a terminal emulator included with macOS ** Windows Terminal, a terminal emulator for Windows 10 and Windows 11 ** GNOME Terminal, a Linux and BSD terminal emulator * Terminal and nonterminal symbols, lexical elements used in specifying the production rules constituting a formal grammar in computer science. Fonts * Terminal (typeface), a monospace font * Terminal (typography), a type of stroke ending Transportation * Airport terminal, a building where passengers embark and disembark aircraft (or cargo is loaded) * Bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Remifentanil
Remifentanil is a potent, short-acting synthetic opioid analgesic drug. It is given to patients during surgery to relieve pain and as an adjunct to an anaesthetic. Remifentanil is used for sedation as well as combined with other medications for use in general anesthesia. The use of remifentanil has made possible the use of high-dose opioid and low-dose hypnotic anesthesia, due to synergism between remifentanil and various hypnotic drugs and volatile anesthetics. Clinical use Remifentanil is used as an opioid analgesic that has a rapid onset and rapid recovery time. It has been used effectively during craniotomies, spinal surgery, cardiac surgery, and gastric bypass surgery. While opiates function similarly, with respect to analgesia, the pharmacokinetics of remifentanil allows for quicker post-operative recovery. Administration It is administered in the form ''remifentanil hydrochloride'' and in adults is given as an intravenous infusion in doses ranging from 0.1 microgram ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fentanyl
Fentanyl, also spelled fentanil, is a very potent synthetic opioid used as a pain medication. Together with other drugs, fentanyl is used for anesthesia. It is also used illicitly as a recreational drug, sometimes mixed with heroin, cocaine, benzodiazepines or methamphetamine, among others. Its potentially deadly overdose effects can be neutralized by naloxone. Fentanyl is commonly used to create counterfeit pills disguised as OxyContin, Xanax, Adderall, among others. It has a rapid onset and its effects generally last under two hours. Medically, it is used by injection, nasal spray, or skin patch, or absorbed through the cheek as a lozenge or tablet. Common adverse effects of fentanyl include nausea, vomiting, constipation, itching, sedation, confusion, and injuries related to poor coordination. Serious adverse effects may include respiratory depression, hallucinations, serotonin syndrome, low blood pressure, or development of an opioid use disorder. Fentan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
