RE: Model estimates based on 1 sample per subject

From: GUZY@xoma.com Subject: RE: [NMusers] Model estimates based on 1 sample per subject Date: 8/19/2003 5:37 PM Dear Toufigh If I understand, you plot effect versus concentration and fit the data using Winnonlin which gave you reasonable values for Vm and Km. When you used NONMEM, my understanding is that you took into account that each observation came from a different rat and you are trying to retrieve both the fixed effect (Mean values) as well as random effects (variability across the population of rats). Since you have only one data point per rat (am I right?) you must fix the intra-individual variance parameters to a specific value. Did you do that? Serge