AUC

Fig. 1. Blood—drug concentration curve used to determine bioavailabiLitv and bioequivalence. C is the maximum dmg concentration in the blood and corresponds to some The AUC (shaded) represents the total amount of orally adininistered dmg the time from points A to B represents dmg onset, from points B to D, the duration MEC = minimum effective concentration MTC = minimum toxic concentration and TI = therapeutic index.

Two similar dosage forms, eg, tablets, that contain the same amount of the same dmg entity and meet USP/NF and current good manufacturing practices (FDA) are referred to as pharmaceutical equivalents (PE). When, upon adiriinistration, such tablets achieve similar profiles of AUC, and... 

Once the steady-state concentration is known, the rate of dmg clearance determines how frequendy the dmg must be adininistered. Because most dmg elimination systems do not achieve saturation under therapeutic dosing regimens, clearance is independent of plasma concentration of the dmg. This first-order elimination of many dmgs means that a constant fraction of dmg is eliminated per unit time. In the simplest case, clearance can be deterrnined by the dose and the area under the curve (AUC) describing dmg concentration as a function of total time ... 

AUC is the area under the curve or the integral of the plasma levels from zero to infinite time. Conversely, equation 1 may be used to calculate input rates of dmg that would produce steady-state plasma levels that correspond to the occurrence of minor or major side effects of the dmg. 

AuC + 2R3P -> R3P.Au.C1 + R3PC12 + Cl or more cheaply, in situ with 2,2 -thiodiethanol, (bis-2-hydroxyethylsulphide) AUCI4 + 2(HOCH2CH2)2S... 

Area under the Curve (AUC) refers to the area under the curve in a plasma concentration-time curve. It is directly proportional to the amount of drug which has appeared in the blood ( central compartment ), irrespective of the route of administration and the rate at which the drug enters. The bioavailability of an orally administered drug can be determined by comparing the AUCs following oral and intravenous administration. 

AUC is the area under the (diug) concentration time curve. 

One solution to the volume problem was proposed using moment analysis. The steady-state volume of distribution (Vss) can be derived from the area under the curve (AUC) and the area under the first moment curve (AUMC). 

The effect of hemodialysis can be derived from the removed fraction (FR) that is the relative amount eliminated from the body during the time (/HD) of one dialysis session. This fraction can be derived from the half-life on dialysis (Tl/2on) or from the area under the curve (AUC) on and off dialysis. 

---