Dear Harish
You can predict peritoneum concentrations only if you do the following:
1: you have observed data in peritoneum and eventually in Plasma
2: You fit the model using the template I gave you
1 compartment is the oral compartment linked to plasma
another compartment is the Plasma compartment
another compartment is the peritoneum compartment
the last compartment is all other organs we call the peripheral compartment.
Now the graph looks like a 3 compartment model with oral input (4 compartments together)
Now if you want to predict peritoneum concentrations, you need t put names of your volumes and clearance.
Let say that V is the volume of the central and its clearance is Cl
Let us say that V2 and Cl2 are the volume of the peritoneum and the inter_compartmental clearance Plasma to Peritoneum
Let us say that V3 and Cl3 are the volume and inter_compartmental clearances Plasma to all other organs, then you can predict peritoneum concentrations
You cannot predict peritoneum concentrations if you get general information about the PK of the drug which follows a 3 compartment model.
Only if you have the data and fit the model tot he data as I told you.
If you did that , then you know if V,V2 or V3 is the volume for peritoneum, same for Clearance.
best Regards
Serge