2 replies to this topic

[Zancong Shen]

Hi, All

I have trouble in writing a model text using PML for a PKPD model in a scenarior when two oral drugs are dosed simultaneously.

The overall meausred PD effect (% of protein reduction) is available for drug 1 alone dosed once daily on first week and drug1 and drug2 dosed simultaneously once daily on second week. I can handle the first week easily.

In second week:

Assuming no synergistic effect and hence E is the addition of two inhiibitory effects which are respectively determined by each drug alone. however, when I try to write the text, it looks like NLME does not recognize two set of PK parameters, eg, Aa1, Aa2, or Ka1, Ka2, or Kin1 and Kin2...etc. It only allows one set of PK or PD parameter, taken a single drug PKPD at default.

 

Does PHX provide the flexibility of doing this type of modeling? Has anyone achieved this?

thanks

zan

[Emily Colby]

Dear Zan,

 

I suggest building the model graphically. Note when you choose from the built-in menus, there is an option to "Edit as Graphical". Then, in the model section of the setup tab, a graphical representation of the model can be viewed and modified. Note that when you click on an item in the model in this mode, you will see various options for each item (such as a compartment, options include multiple dosepoints). If extra parameters are needed, right-click on the blank workspace and select insert > parameter. Then, name the parameter at the bottom in the options tab. The text is also updated automatically.

 

If editing in text mode, one only needs to add stparm() and fixef() statements to add a parameter. One can simply follow the pattern of the existing stparm() and fixef() statements when doing so.

 

Best regards,

Emily Colby

[Zancong Shen]

Hi Emily,

It sounds this is the merit of having the cool graphical model in PHX. Thanks for the useful tips. I will play with it.

Best regards

zan