modeling different routes

Hi, dear I’m trying to build a model that combines all dosing routes for a drug. I’m wondering how to distinguish each route in NLME text code. The model I built seems to get all routes at the same time. I attched a sample data in the file. Hope someone could give me a clue. Mengjie [file name=routes.xlsx size=12891]Certara | Drug Development Solutions (12.6 KB)

Hi your data is like the follwoing ID Time Conc Doseiv Doseim 1 0 3800 3800 i.m 1 0.01 0.2792 i.m 1 0.02 0.4384 i.m 1 0.04 0.5327 i.m 1 0.08 0.4738 i.m 1 0.125 0.3813 i.m 1 0.167 0.3008 i.m Above is telling nlme that we have two doses of 3800 at time 0 when in doseiv and one in doseim To tell nlme that you have dose only in im you need to have empty Doseiv ID Time Conc Doseiv Doseim 1 0 3800 i.m 1 0.01 0.2792 i.m 1 0.02 0.4384 i.m 1 0.04 0.5327 i.m 1 0.08 0.4738 i.m 1 0.125 0.3813 i.m 1 0.167 0.3008 i.m …