Some time ago I was trying to learn Phoenix models using pml language: I have revisited this topic today and I am having difficulty with my earlier work. When inserting an observation compartment it should connect with the central compartment with an arrow so that it is evident that the observations being made on the central compartment. My approach has been to work with very simple models that I have already run in the classic models.
The specific example I attach is for a 1 cpt model with a lag time; first order elimination and first order absorption of 20mg drug. I do not know to include the observation compartment. I am planning a "simple" fitting
Advice is most welcome;