PK turnover model

Phoenix Certara Forums Modelling and Simulation
1

Hi,

I am studying the turnover of proteins, peptides and antibodies (Dr. Dan Weiner’s textbook). There is an application about the turnover of hormone (PK30). A volunteer received a 40 ug/kg dose D of IgX (sc). The IgX concentrations were measured before and after the dose. WNL5 ASCII format was used to calculation PK parameters (V, ka, turn-over rate and Cl etc). Please see the attachment.

I am wondering if there is any other method to do PK turnover model besides WNL5 ASCII format. I tried Indirect response model (IR) and PKPD model. But it seems that these two models are for PD data.

Thank you!

LLLi

PK30 turnover model sc dosing.phxproj (261 KB)

2

Here we go. The project has been translated into Phoenix.

Let me know if you need further explanations. We need to write the code for this case.

Best Regards

Serge

PK30 turnover model sc dosing.phxproj (851 KB)

3

LLLi, you may also wish to join the webinar this Thrusday and follow this new sub-forum;

https://support.certara.com/forums/forum/34-pml-school/

It is dedicated to teaching people the use of the Phoenix modelling language as it is more versatile and powerful than the old ASCII code and engine.

Simon

4

Hi All,

I wanted to transfer ASCII code into PML but failed. Would you please help me to figure it out? Please see the details in the project attached.

Background: iv of hormone (so it is a turnover model); infusion time = 0.0167 hr; infusion dose = 36630.

Thank you very much!

LLLi

Turnover IV dosing.phxproj (550 KB)

5

Dear LLi

You had few coding errors.

First the if condition in the main code is not as you wrote. I fixed it.

Second you did not write the right initial condition for C2. I fixed it.

Let me know if the results look good to you now.

the updated project is attached.

best Regards

Serge

Turnover IV dosing.phxproj (826 KB)

6

Hi Serge,

Why you freeze Tlag=0 in your project (the first project that you posted)?

I removed the freeze in the code and Tlag is less than 0.

Thank you!

LLLi

7

Hi Serge,

Thank you for your reply.

I have another question about the if condition.

In my project, The format is In=(t<=t2?A:C)

If the condition is more complex, for example:

if t<t1, In=A, if t1<t<t2, In=B, if t>t2, In=C.

How to write this if statement in the code?

Furthermore, in turnover model, the deriv(C=) contains “In” while in the other model, there is no In in deriv(A=). Why?

Thank you!

LLLi

8

I am not sure about the project you are talking about. Can you send it to me?

9

In that case you would write

ln=(t<t1?A:t<t2?B:t>t2?C)

about the next question I just translated the model you gave me. I am not sure it that question related to what I fixed.

Best

SERGE

10

Hi Serge,

Thank you for your reply!

Sorry for the confusion. The project was uploaded by you in this post (PK30 turnover model sc dosing.phxproj). Here I uploaded it for your reference.

Thank you!

LLLi

PK30 turnover model sc dosing.phxproj (851 KB)