Is there an easy way to determine plasma concentrations for the shallow and deep compartments of a three compartment model in a project file. I’m trying to plot the shallow and deep compartment plasma concentrations as a function of time and then plot the PD effects as a function of time on the same plot to determine whether the effects can be attributed to one of the compartments. Thank you for your help. -Marc
Dear Marc The only way I can see is to built the model using the dclearance parametrization, uncheck the closed form. When you uncheck the closed form, then you can see in model text the definition of thw two deep compartments as C2=A2/V2 and C3=A3/V3 . THEN YOU PUT INITIAL VALUES FOR ALL THE PARAMETERS and put C2 and C3 as the responses you want to get simulated values. I am attaching a simple project that deos the job. I hope it helps. best Serge [file name=marc_shallow_deep.phxproj size=354157]Certara | Drug Development Solutions (346 KB)
Thanks Serge. That’s a pretty creative way to do it. I’ll give it a try and follow up. -Marc
Mike, here is an example graph with C2 and C3 on the Y2 axis, although of course you would most likely be placing the PD data on that. 
I wanted to clarify that Serge’s table statement (on the tab Run Options) could have produced a richer output by changing the Times line from; seq(0,10,1) to e.g. seq(0,2.5,0.1), seq(3,10,1) to give a richer ‘sampling’ every 6 mins to 2.5 h, and then 1 h thereafter. And if it was from a fitting you could also request e.g. CObs and EObs on the When Observe: line to allow you to include the observed data in this plot too. Simon PS Also don’t forget that on the Plot Options tab, Graphs, you can increase the number of input work sheets to overlay other datasets, i.e. observed data from the original dose versus simulations
