Method of residuals: estimation of absorption and elimination rate constants having comparable values.

An equation was developed to be used with the method of residuals for the analysis of the linear one-compartment open model. This equation can provide information about the magnitude of the ratio of rate constants, without assuming that the terminal phase reflects solely either an elimination or an absorption process, as must be done for the graphical techniques. It also enhanced the analytical power of the method of residuals in that it gave better estimates of the absorption rate constant when the latter and the elimination rate constant have comparable magnitudes.