Use of urinary excretion data

There are two methods that permit us to compute some pharmacokinetic parameters from urinary excretion data. 

Profile representing cumulative amount of drug in the urine (X ) 

Plot representing amount (X) of drug in blood or body 

The amount remaining lo be excreted sigma minus method theoretical considerations 

A plot of [(Xu) , - (Xu) J (i.e. the amount of drug remaining to be excreted, which also equals the amount of drug remaining in the blood) against time (Eq. 3.20) should provide a straight line on semilogarithmic paper, as illustrated in Fig. 3.17. 

---