# Co-modeling of multiple observed data profile

**URL:** <https://forum.certara.com/t/co-modeling-of-multiple-observed-data-profile/3517>\
**Category:** Modelling and Simulation\
**Created:** [November 16, 2020, 3:53am UTC](https://forum.certara.com/t/co-modeling-of-multiple-observed-data-profile/3517 "2020-11-16T03:53:02Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![dinhbt1988](https://avatars.discourse-cdn.com/v4/letter/d/8dc957/32.png) [@dinhbt1988](https://forum.certara.com/u/dinhbt1988)\
**Post date:** [November 16, 2020, 3:53am UTC](https://forum.certara.com/t/co-modeling-of-multiple-observed-data-profile/3517/1 "2020-11-16T03:53:02Z")

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Hello,

I am working on PK modeling of drug concentrations in both plasma and saliva. Could you please help to give instruction on how to model drug concentration in multiple observed compartments simultaneously? Thank you!

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**Author:** ![SimonDavis](https://avatars.discourse-cdn.com/v4/letter/s/d9b06d/32.png) [@SimonDavis](https://forum.certara.com/u/SimonDavis)\
**Post date:** [November 16, 2020, 8:17am UTC](https://forum.certara.com/t/co-modeling-of-multiple-observed-data-profile/3517/2 "2020-11-16T08:17:54Z")

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The easiest way to do this is create your dataset to have a column per observation location. Have a look at the 2 dose point example in the manual

[https://onlinehelp.certara.com/phoenix/8.3/index.html#t=topics%2Fnlmeextwodosept.htm%23XREF\_97540\_Creating\_a\_two](https://onlinehelp.certara.com/phoenix/8.3/index.html#t=topics%2Fnlmeextwodosept.htm%23XREF_97540_Creating_a_two)

the principle is the same for 2 or more sample points.

I think there maybe an example too from one of the PML webinars, but have a try and post your project if you get stuck.

Simon.

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**Author:** ![bwendt](https://avatars.discourse-cdn.com/v4/letter/b/f4b2a3/32.png) [@bwendt](https://forum.certara.com/u/bwendt)\
**Post date:** [November 16, 2020, 8:32am UTC](https://forum.certara.com/t/co-modeling-of-multiple-observed-data-profile/3517/3 "2020-11-16T08:32:07Z")

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There is one example among the PML School webinars where we show how to deal with two observations: parent and metabolite:

[https://support.certara.com/forums/topic/928-lesson-2-parent-and-metabolite-kinetics/](https://support.certara.com/forums/topic/928-lesson-2-parent-and-metabolite-kinetics/)

Please take a look at the recorded session where we show the steps to build this model from scratch.

Bernd