Drug disposition analysis: a comparison between budesonide and fluticasone.

The characterisation of distribution and elimination properties of a drug is usually done using parameters like clearance and distributional volumes. To refine this characterisation, in this paper, we use drug disposition analysis to compare the distribution and elimination of the two glucocorticosteroids budesonide and fluticasone propionate, known to differ in this respect. This gives a more detailed description of the well known differences in distributional volumes using concepts like mean residence time and fraction of dose outside the central compartment. It clearly shows that fluticasone, although having lower plasma concentrations, still resides in the body in appreciable quantities.