Area under the concentration vs time

AUC, area under the concentration vs time curve N/A, not applicable. 

Figure 5.2 Plasma concentration curve of drug after single and repeated administration Csj. nax, maximal steady-state plasma concentration after repeated administration Css av, average steady-state concentration after repeated administration Css mm- minimal steady-state concentration after repeated administration n. maximal plasma concentration after single oral dose t Inax. time to maximal concentration after single oral dose t plasma half-life after single oral dose AUC, area under the concentration vs. time curve...

Distributed pharmacokinetics is characterized not only by spatially dependent concentration profiles but also by dose-response relationships that become spatially dependent. For example, biological responses such as cell kill are often quantified as functions of area under the concentration-vs.-time curve (ALIC). In compartment models, response is frequently correlated with the area under the plasma-concentration-vs.-time curve, where... 

PKpharmacokinetics, maximum plasma concentration, CL systemic clearance, AUC area under the concentration vs. time curve, SNP single-nucleotide polymorphism... 

Upon opening the ozone chamber to introduce samples, a concentration gradient was produced. For this reason the subsequent time involved for equilibrium to be reestablished, exposure time was not used as the only gauge of exposure in reciprocity measurements. Under these circumstances, the area under the concentration vs time curve appears to be a better measure of exposure of the sample to ozone. This area factor was kept constant over a range of concentration conditions. 

The elimination half-life of the "second component" discussed previously was 1.9 h and the mean area under the concentration vs time curve (AUC) was 8.2 mg/L h after a single oral dose of 320 mg (De Bemardi Di Valserra et al., 1994). The AUC of the "second component" produced by a 640-mg rectal dose of saw palmetto extract was 10 mg/L x h, and plasma levels were detectable up to 8 h post-dose (De Bernardi Di Valserra and Tripodi, 1994). 

The toxic effect is often a function of the concentration of the toxicant multiplied by time of exposure, or the concentration in a tissue multiplied by the time. The integral of the concentration-time function is called AUC, the acronym for the area under the curve (Figure 8.2). AUC is easily determined by measuring the area under the concentration vs. time, either by mathematical integration if the function is known or by some more pragmatic methods. AUC is useful to determine the uptake or bioavailability of substances. AUC in blood can be determined after intravenous injection and compared with the AUC after oral administration. 

Fig. 8.11 Underestimation of CBV caused by truncation of the concentration-vs.-time curve. CBV is usually calculated by measuring the area under the concentration-vs.-time curve. Example curves are shown reflecting normally perfused tissue (solid curve) and underperfused tissue (dashed curve). The area under the dashed curve is greater than that under the solid curve, reflecting elevated CBV in the underperfused tissue. However, if the PWI scan is terminated at the time indicated by the vertical line, the integrated area under the dashed curve is lower, and a low CBV value is erroneously calculated...

As a result of differing rates of hydrolysis, 2 -esters of erythromycin differ from their parent and each other in terms of peak serum concentrations, length of time to achieve that concentration, and area under the concentration vs. time curve (AUC) [63, 69, 248]. Roxithromycin is characterized by relatively high serum concentrations that are several-fold greater than those achieved by erythromycin [244, 249-251]. In contrast, clarithromycin produces relatively moderate serum concentrations, but achieves much higher tissue concentrations than roxithromycin [252, 253]. Azithromycin gives lower serum concentrations, but very high tissue... 

Coulometry. If it can be assumed that kinetic nuances in the solution are unimportant and that destmction of the sample is not a problem, then the simplest action may be to apply a potential to a working electrode having a surface area of several cm and wait until the current decays to zero. The potential should be sufficiently removed from the EP of the analyte, ie, about 200 mV, that the electrolysis of an interferent is avoided. The integral under the current vs time curve is a charge equal to nFCl, where n is the number of electrons needed to electrolyze the molecule, C is the concentration of the analyte, 1 is the volume of the solution, and F is the Faraday constant. 

Area under the concentration- inbloodstream vs. time curve... 

Toxicokinetic risk factors are those that can lead to increased Cmax (maximum concentration) and/or AUC (area under the curve of the concentration vs. time plot) of a given drug in a patient s liver. The drug in question can be the parent drug, its toxic metabolite, or a combination. The liver s increased exposure to drugs can be caused by increased drug absorption (e.g., for an orally administered medication) and/or decreased drug clearance. Some of the major causes of toxicokinetic risk factors are summarized next. 

Finally, preliminary diagnostic evaluation criteria, based on preventive identification of critical areas of interest on the monitored item, spatial concentration of localized AE events as compared with average AE event density and evolution of local event concentration vs time and/or plant parameters, have been worked out and submitted to extensive testing under real operation conditions. Work on this very critical issue is still to be consohdated. 

Bioavailability was assessed from measurement of the area under the curve (AUC) of whole blood lead concentration vs time (Blood AUC) or from measurements of the lead concentrations in bone, kidney or liver (the arithmetic mean of the three tissues is shown in the table). Data are from Casteel et al. (1997) and EPA (1996a, 1996b, 1996c). 

The bioavailability of a drug by various routes may also be determined by comparing the area under the curve (AUC) obtained from the plasma concentration vs. time curve after intravenous and other routes of administration 9... 

FIGURE 4.3 Hypothetical plasma concentration-vs.-time curve after a single oral drug dose. Calculation of the area under the plasma level-vs.-time curve (AUC) requires extrapolation of the elimination-phase curve beyond the last measurable plasma concentration, as shown by the dotted line. 

PK = pharmacokinetic Cl = clearance AUC = area under the plasma concentration vs. time curve ERBT = erythromycin breath test IM = intramuscular IV = intravenous... 

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