Re: lagged concentrations

From: Leonid Gibiansky Subject: Re: [NMusers] lagged concentrations Date: 10/29/2003 4:35 PM My guess is that you did not have a dose records that assign dose to the compartments 2 and 3 (is this what you mean by "I did not initialise compartment 2 and 3"). You should put the same dose to all compartments at the same time. According to the NONMEM guide: " Absorption lag applies to the initiating dose and to all subsequent additional doses. If an absorption lag parameter is defined by PK for the dose compartment and has a positive value, then the dose ... is actually introduced into the system at a "lagged time" equal to the time at which the dose would ordinarily be introduced plus the value of the absorption lag parameter. " This gives you exactly the same profiles in each compartment, but shifted by ALAG(). Without dose, NONMEM solves equations A'=-K*A with initial condition A = 0 and gives you the perfectly correct answer A(t) = 0 Good luck Leonid