The non-compartmental steady-state volume of distribution revisited

The lack in the literature of a simple, yet general and complete derivation of the widely used equation for non-compartmental calculation of steady-state volume of distribution is pointed out. It is demonstrated that the most frequently cited references contain an overly simplified explanation. The logical gap consists in doubly defining the same quantities without a proof the definitions are equivalent. Two alternative solutions are proposed: analytical derivation and hydrodynamic analogy. It is shown, that the problem can be analyzed in a purely macroscopic framework by utilizing the integral mean value of the function, without the need to resort to statistical distributions.