A new method for the determination of steady-state volume of distribution of drugs with rapid distribution

Abstract

Conventional methods for determination of the volume of distribution at steady-state (Vss) often involve a nonlinear regression program and/or detailed compartmental analysis. A new method for estimating Vss of a drug exhibiting a rapid distribution has been described based on the instantaneous equilibrium after intravenous bolus dose. This method needs simple mathematical skills only, involving calculation of the area under the plasma concentration versus time curve. Single dose plasma levels generated for five drugs, which are known to have a rapid distribution, have been utilized to examine the applicability of this method. This approach is as adequate as the conventional methods but offers simplicity in data handling.