Analysis of pharmacokinetic and pharmacodynamic data

The estimated area under the curve from time point zero to infinity (AUC(q j) is calculated using the trapezoidal rule. There are two steps in this process  

Calculate the trapezoidal area between all adjacent time points 

This calculation is an estimate of the real AUCp y but a meaningful and useful estimate. By progressively increasing the sampling frequency we could obtain more and more precise measurements, but pragmatism dictates frequency, and a reasonable frequency produces a useful estimate of AUC 

Elimination of a drug is measured using a quantity called a half-life 1 /2)- A half-life is the time required to reduce the plasma concentration to 

Excretion concerns the removal of a drug compound from the body. Both the original (parent) drug compound and its metabolites can be excreted. The primary mode of investigation here is excretion balance studies. A radiolabeled drug compound is administered and radioactivity is then measured from excretion sites (for example, urine, feces, expired air). These studies provide information on which organs are involved in excretion and the time course of excretion. 

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