Clinical Trials

❘❙❚■ Chapter 13 | Bioequivalence TrialsFigure 2. Determination of the elimination phase and elimination rate constant.2 –Elimination phase1 –Log concentration (ng/mL)0 ––1 ––2 –Finalregressionline|0|2|4|6|8|10Time relative to dose (hours)AUC 0–∞The next step in the PK parameter calculation is to obtain the AUC 0–∞– the totalamount of drug present in the blood – by extending the ‘plasma concentrationover time’ profile to infinity.Assuming that the exponential elimination process will continue beyond the lastobserved concentration at time t, the extended area after t is C t/ λ [1–4]. This gives:AUC 0–∞= AUC 0–t+ AUC t–∞= AUC 0–t+ C t/ λFor the anagrelide data, we get:AUC 0–∞= 12.03 + 0.09 / 0.58 = 12.18124