2 replies to this topic

[tienle]

Good afternoon, 

 

I am trying to build a PopPk model for a drug with its metabolite as a sequential model (parent drug -> metabolite 1 -> metabolite 2).

 

I am trying to model the fraction excreted in urine compartment and fraction metabolized, and want to specify in the model that fe + fm = 1. I do not know how to code that in the textual model. Can I please get help with this issue?

 

Another issue, when I was trying to model simultaneous plasma and urine data, my final estimates for fe parameters were not estimated by the model. I kept getting an error message saying:

"Fixed effect 'tvFe' is not used and will be frozen

Random effect 'nFe' is not used

Structural parameter 'Fe' is not used"

Could anyone please explain what went wrong here? Thank you!

 

 

I attached the picture of the graphical model I built below. Thank you so much and I greatly appreciate any help!

 

C: parent drug

C2: metabolite 1

C3: metabolite 2

A0: urine data for parent drug

A4: urine data for metabolite 1

A5: urine data for metabolite 2

Q_C_C2: formation clearance (parent drug to metabolite 1)

Q_C2_C3: formation clearance (metabolite 1 to metabolite 2)

Cl: renal clearance of parent drug

Cl_C2_A4: renal clearance of metabolite 1

Cl_C3_A5: renal clearance of metabolite 2

 

 

Attached Thumbnails

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Edited by tienle, 20 February 2023 - 06:32 PM.

[cradhakr]

Hi,

 

I have attached an link to PML School conducted by Certara - this could be of use to you to model parent and metabolite.

 

https://support.cert...olite-kinetics/

 

To address your specific question on tvFe, is it possible for you to share the project file for us to investigate further? If you would like to keep it confidential please e-mail to support@certara.com

 

Thanks & Regards

Mouli

[tienle]

Hi,

 

I have attached an link to PML School conducted by Certara - this could be of use to you to model parent and metabolite.

 

https://support.cert...olite-kinetics/

 

To address your specific question on tvFe, is it possible for you to share the project file for us to investigate further? If you would like to keep it confidential please e-mail to support@certara.com

 

Thanks & Regards

Mouli

 Hi Mouli, 

 

Thank you for sending the lecture note for parent and metabolite modeling. I appreciate it!

 

I am happy to share the project. I will email it to support@certara.com shortly. 

 

Thank you,

 

Tien