An approach for determination of chronopharmacokinetic parameters of methotrexate.

In classical pharmacokinetic studies, the organism is represented by one or several compartments described by a system of linear differential equations with constant coefficients. A system of linear differential equations can not describe the compartmental model in the presence of chronobiological variations. The purpose of this study is to calculate the chronopharmacokinetic parameters of Methotrexate, which presents this type of variation.