Area under curve, AUC

In the total plasma response approach, the bioavailability of a compound is determined by measuring its plasma concentration at different times (up to weeks) after single or long-term ingestion of the compound from supplements or food sources. Generally, a plasma concentration-versus-time plot is generated, from which is determined the area-under-curve (AUC) value used as an indicator of the absorption of the componnd. Here, the term relative bioavailability is more appropriate since AUC valnes of two or more treatments are usually compared. This is in contrast to absolnte bioavailability for which the AUC value of the orally administered componnd is compared to that obtained with intravenous administration taken as a reference (100% absorption). 

Figure 3.3 Determination of area under curve (AUC) of a compound in the body (see Table 3.1 for calculations).

Area under curve (AUC] The total area under the plot-of-drug concentration versus time following either a single dose or multiple doses of a specific drug product (e.g., formulation) in a specific patient by a specific route of administration. 

Chilamkurti [90] Area under curve (AUC) Height of curve at maximum upper punch force Width of curve at half-maximum upper punch force Slope during compression Slope during decompression... 

Test Items. As a rule, the pharmacokinetic parameters of test substances such as maximum concentration (Cmax) and time to reach maximum concentration (Tmax), area under curve (AUC), elimination half-life, clearance, distribution volume, bioavailability, etc., and pharmacokinetic nonlinearity are studied. The pharmacokinetics of metabolites of the test substance should be examined if necessary. 

The pharmacokinetic properties of AR-A014418 have been studied in Sprague-Dawley rats. After per oral dosing of 1 p.mol/kg of AR-A014418, the maximal total concentration (Cmax) in plasma was 3.75 p.M with an area under curve (AUC) of 22.4 p.M h and the half-life was determined to be 8.7 h with a Tmax of 0.26 h. After an i.v. bolus dose of 3 p.mol/kg, followed by an infusion of 3 p.mol/kg/h over 2 h to obtain a steady state between plasma and... 

Cell viability. Exponentially growing HL-60 cells, 15 x 106 in 75.0 mL of RPMI 1640, were incubated with either ATRA, or UDMA or BDDMA for five days. The total cell number was determined every day using the trypan blue dye exclusion test. Both the cellular proliferation - as area under curves (AUC) - and cellular mortality were calculated. 

Figure 4. Area Under Curve (AUC) represents the success rate and prediction rate.

Solid dispersion is defined as one type of method to produce an amorphous compound by incorporating a hydrophobic drug into a hydrophilic carrier (Chiou and Riegelman 1971). It is one of the most studied methods to solubilize and to enhance dissolution rate of biopharmaceutical classification system (BCS) class 2 compounds. For instance, a solid dispersion of ritonavir (Law et al. 2001), ER-3421 (a dual 5-lipoxygenase/cyclooxygenase inhibitor Kushida et al. 2002), was found to have a much higher dissolution rate than the crystalline counterpart and resulted in higher area under curve (AUC) and Cmax in the in vivo study. 

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