Bioequivalence and Bioavailability Forum

dear atish !

you may find also pages 128-129 of Cawello et al. (2003). Parameters for Compartment-free Pharamcokinetics. Shaker Verlag, Aachen of interest.

on assumption of dose-proportionality the following conditions hold

1) a dose of zero leads to an AUC of zero
2) the ratio of AUC/dose is constant for all doses (irrespective of equally or non-equally spaced doses)

a plot the ratio of AUC/dose on the y-axis and dose on the x-axis should therefore be a straight line parallel to the x-axis.

- in the case that the ratio of AUC/dose increases at higher doses you may have an saturable metabolism at higher doses
- in the case that the ratio of AUC/dose decreases at higher doses you may have an saturable absorption at higher doses

hope this helps

martin