RE: indirect response model

From: "Luann Phillips" luann.phillips@cognigencorp.com Subject: RE: [NMusers] indirect response model Date: Thu, August 19, 2004 10:41 am Kai, I would try adding your baseline measurements to the dataset starting at time=0,initialize the amount in compartment 4 to an appropriate value, and include your equation for Rcort in $PK if it is not dependent on continuous time (TIME) or in $DES if dependent on continuous time (T). To initialize the amt in cmt=4, I would add an additional dose record with cmt=4 at time=0 with amt=the measurement of the endogenous substance at time=0 (i.e., the first observation from your baseline data would double as a dose and a measurement). If your concerned about measurement error for the time=0 measurement of the endogenous substance, you can estimate F4=1+eta(n) or F4= 1*(1+eta(n)), etc. where the eta would represent the measurement error for the substance at time=0. Note: Because all of the baseline records for the endogenous substance would come before the first dose of the drug, cp will be zero throughout the baseline period and eff=1. Regards, Luann _______________________________________________________