How to create 1 observer 'total fraction of dose' for multiple molecules/enzymes

[nina-nauwelaerts]

Hi

I am working on a compound that is metabolized via multiple routes, including different UGT enzymes. The container observer 'Total fraction of dose' gives me the fraction for each of the enzymes. However, I would like to have a single observer that gives immediately the total fraction for all UGT enzymes.
I am aware of the examples in the manual, but I'm still not able to create this observer.

Thanks!

[Yuri05]

One possibility to do this is:

• Caclulate the total amount for each metabolite
• Define the observer as (Total_amount_metabolite_1+...+Total_amount_metabolite_N) / Total_DrugMass_of_the_parent_compound

E.g. see the attached example. TotalFractionDose_OverAllMetabolites_02.zip
Here the Compound C1 is metabolized by 2 Enzymes (Enzyme_1 and Enzyme_2) building 2 metabolites: C1-Enzyme_1-aa Metabolite and C1-Enzyme_2-bb Metabolite

1. In the molecules building block, I introduce the Parameter "Total drug amount in organsim" for the first metabolite and define is as the sum of all amounts of this metabolite within the organism (important: set parameter type to Property)
   
2. Same for the 2nd metabolite (here I can just use the same formula which I created for the first metabolite)
   
3. Now I define new container observer for the total fraction of all metabolites
   
4. The formula of the new observer is then:
   
5. Now you can plot the new observer