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Peak Plasma Levels
Cmax is the maximum (or peak) serum concentration that a drug achieves in a specified compartment or test area of the body after the drug has been administered and before the administration of a second dose. It is a standard measurement in pharmacokinetics. Description Cmax is the opposite of Cmin, which is the minimum (or trough) concentration that a drug achieves after dosing. The related pharmacokinetic parameter tmax is the time at which the Cmax is observed. After an intravenous administration, Cmax and tmax are closely dependent on the experimental protocol, since the concentrations are always decreasing after the dose. But after oral administration, Cmax and tmax are dependent on the extent, and the rate of drug absorption and the disposition profile of the drug. They could be used to characterize the properties of different formulations in the same subject. Short term drug side effects are most likely to occur at or near the Cmax, whereas the therapeutic effect of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serum (blood)
Serum () is the fluid and solute component of blood which does not play a role in Coagulation, clotting. It may be defined as blood plasma without the clotting factors, or as blood with all cells and clotting factors removed. Serum includes all proteins not used in Coagulation, blood clotting; all electrolytes, antibodies, antigens, hormones; and any exogenous substances (e.g., drugs or microorganisms). Serum does not contain white blood cells (leukocytes), red blood cells (erythrocytes), platelets, or clotting factors. The study of serum is serology. Serum is used in numerous diagnostic tests as well as blood typing. Measuring the concentration of various molecules can be useful for many applications, such as determining the therapeutic index of a drug candidate in a clinical trial. To obtain serum, a blood sample is allowed to clot (coagulation). The sample is then centrifuged to remove the clot and blood cells, and the resulting liquid wikt:supernatant, supernatant is serum. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concentration (chemistry)
In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: '' mass concentration'', ''molar concentration'', ''number concentration'', and ''volume concentration''. The concentration can refer to any kind of chemical mixture, but most frequently refers to solutes and solvents in solutions. The molar (amount) concentration has variants, such as normal concentration and osmotic concentration. Etymology The term concentration comes from the word concentrate, from the French , from con– + center, meaning “to put at the center”. Qualitative description Often in informal, non-technical language, concentration is described in a qualitative way, through the use of adjectives such as "dilute" for solutions of relatively low concentration and "concentrated" for solutions of relatively high concentration. To concentrate a solution, one must add more solute (for example, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compartment (pharmacokinetics)
In pharmacokinetics, a compartment is a defined volume of body fluids, typically of the human body, but also those of other animals with multiple organ systems. The meaning in this area of study is different from the concept of anatomic compartments, which are bounded by fasciae, the sheath of fibrous tissue that enclose mammalian organs. Instead, the concept focuses on broad types of fluidic systems. This analysis is used in attempts to mathematically describe distribution of small molecules throughout organisms with multiple compartments. Various multi-compartment model A multi-compartment model is a type of mathematical model used for describing the way materials or energies are transmitted among the ''compartments'' of a system. Sometimes, the physical system that we try to model in equations is too complex, so ...s can be used in the areas of pharmacokinetics and pharmacology, in the support of efforts in drug discovery, and in environmental science. In humans and related ... [...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] |
Cmin
Cmin is a term used in pharmacokinetics for the minimum blood plasma concentration reached by a drug during the time interval between administration of two doses. This definition is slightly different from Ctrough, the concentration immediately prior to administration of the next dose. Cmin is the opposite of Cmax, the maximum concentration that the drug reaches. Cmin must be above certain thresholds, such as the minimum inhibitory concentration (MIC), to achieve a therapeutic effect. In most cases Cmin is directly measurable. At steady state the minimum plasma concentration can also be calculated using the following equation: :C_= \frac\times\ :''S'': salt factor :''F'': bioavailability :''D'': dose :''k'': elimination constant :''ka'': absorption constant :''Vd'': volume of distribution :''τ'': dosing interval Cmin is also an important parameter in bioavailability and bioequivalence Bioequivalence is a term in pharmacokinetics used to assess the expected in vivo biolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adverse Drug Reaction
An adverse drug reaction (ADR) is a harmful, unintended result caused by taking medication. ADRs may occur following a single dose or prolonged administration of a drug or result from the combination of two or more drugs. The meaning of this term differs from the term "side effect" because side effects can be beneficial as well as detrimental. The study of ADRs is the concern of the field known as ''pharmacovigilance''. An adverse drug event (ADE) refers to any unexpected and inappropriate occurrence at the time a drug is used, whether or not associated with the administration of the drug. An ADR is a special type of ADE in which a causative relationship can be shown. ADRs are only one type of medication-related harm, as harm can also be caused by omitting to take indicated medications. Classification ADRs may be classified by e.g. cause and severity. Cause *Type A: Augmented pharmacologic effects - dose dependent and predictable :Type A reactions, which constitute approximate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bioequivalence
Bioequivalence is a term in pharmacokinetics used to assess the expected in vivo biological equivalence of two proprietary preparations of a drug. If two products are said to be bioequivalent it means that they would be expected to be, for all intents and purposes, the same. Birkett (2003) defined bioequivalence by stating that, "two pharmaceutical products are bioequivalent if they are pharmaceutically equivalent and their bioavailabilities (rate and extent of availability) after administration in the same molar dose are similar to such a degree that their effects, with respect to both efficacy and safety, can be expected to be essentially the same. Pharmaceutical equivalence implies the same amount of the same active substance(s), in the same dosage form, for the same route of administration and meeting the same or comparable standards." For The World Health Organization (WHO) "two pharmaceutical products are bioequivalent if they are pharmaceutically equivalent or pharmaceut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bioavailability
In pharmacology, bioavailability is a subcategory of absorption and is the fraction (%) of an administered drug that reaches the systemic circulation. By definition, when a medication is administered intravenously, its bioavailability is 100%. However, when a medication is administered via routes other than intravenous, its bioavailability is generally lower than that of intravenous due to intestinal endothelium absorption and first-pass metabolism. Thereby, mathematically, bioavailability equals the ratio of comparing the area under the plasma drug concentration curve versus time (AUC) for the extravascular formulation to the AUC for the intravascular formulation. AUC is used because AUC is proportional to the dose that has entered the systemic circulation. Bioavailability of a drug is an average value; to take population variability into account, deviation range is shown as ±. To ensure that the drug taker who has poor absorption is dosed appropriately, the bottom value o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Area Under The Curve (pharmacokinetics)
In the field of pharmacokinetics, the area under the curve (AUC) is the definite integral of the concentration of a drug in blood plasma as a function of time (this can be done using liquid chromatography–mass spectrometry). In practice, the drug concentration is measured at certain discrete points in time and the trapezoidal rule is used to estimate AUC. Interpretation and usefulness of AUC values The AUC (from zero to infinity) represents the ''total drug exposure across time''. AUC is a useful metric when trying to determine whether two formulations of the same dose (for example a capsule and a tablet) result in equal amounts of tissue or plasma exposure. Another use is in the therapeutic drug monitoring of drugs with a narrow therapeutic index. For example, gentamicin is an antibiotic that can be nephrotoxic (kidney damaging) and ototoxic (hearing damaging); measurement of gentamicin through concentrations in a patient's plasma and calculation of the AUC is used to guide t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cmean (pharmacology)
Cavg is the average concentration of a drug in the central circulation during a dosing interval in steady state. It is calculated by :C_=\frac where AUC_ is the area under the curve and \tau the dosing interval. See also * Area under the curve (pharmacokinetics) In the field of pharmacokinetics, the area under the curve (AUC) is the definite integral of the concentration of a drug in blood plasma as a function of time (this can be done using liquid chromatography–mass spectrometry). In practice, the drug ... * Cmax (pharmacology) References Pharmacokinetic metrics {{Pharmacology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
