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problem on multi-dose simulution #441

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xixi-1995 opened this issue Jan 7, 2020 · 8 comments
Open

problem on multi-dose simulution #441

xixi-1995 opened this issue Jan 7, 2020 · 8 comments

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@xixi-1995
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@xixi-1995 xixi-1995 commented Jan 7, 2020

hi, everyone
I met one problem when I did multi-dose simulation,
image
I have tried to simulate lower multi-dose ,it goes well, when I tried to simulate higher multi-dose, it shows error like the picture described, I'm wondering how to solve this problem and how to understand the error I have met?
I really need your help

@Yuri05

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@Yuri05 Yuri05 commented Jan 7, 2020

The error means that the underlying ODE system could not be numerically solved.
You can try to increase the number of internal solver steps in the solver settings (make sure that Advanced parameter mode is selected). However the predefined value of 100000 is already pretty high; increasing it will with high probability result in the same error after longer computation time
grafik

The problem occurs between the last output time point before 1560 min and 1560min. E.g. if you simulate with 4 points/h in this time interval, the problem begins somewhere in the time interval [1545..1560] min. Try to find a time bound within this time interval where the numerical problem begins.

E.g. do something like in the screen below. You will get a new location of the problematic output time (e.g. 1550.1234 min). After that set a simulation time to the last output time point before before the new problematic time (e.g. for my example it would be 1550.1225 min), simulate and try to investigate the simulation results to get a hint what might go wrong.
grafik

@xixi-1995

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@xixi-1995 xixi-1995 commented Jan 8, 2020

@Yuri05 thanks for your patiently reply , I have tried to adjust resolution as you mentioned above, it seems that I need try something more as the end-time is up to 168h. it is noted that I have tried to do a multi-dose simulation with dosing interval is12h,it seems go well, while dosing interval=24h seems to have errors, I'm still confused.

@Yuri05

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@Yuri05 Yuri05 commented Jan 8, 2020

Can you upload your project?

@xixi-1995

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@xixi-1995 xixi-1995 commented Jan 8, 2020

hi@Yuri05 ,thanks for your help. Here is my PK-Sim file, the simulation of po-60mg-multi-144h-bid goes well.while po-60mg-multi-144h-qd seems to have something wrong.
Uploading Duloxetine.zip…

@Yuri05

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@Yuri05 Yuri05 commented Jan 8, 2020

@xixi-1995 you didn't upload the project

@xixi-1995

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@xixi-1995 xixi-1995 commented Jan 8, 2020

oh sorry,
Duloxetine.zip

@Yuri05

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@Yuri05 Yuri05 commented Jan 8, 2020

ok, that's a numerical problem with Weibull formulations with lag time > 0.
As a workaround: approximate your Weibull dissolution function with a table. The easiest way to do this:

  1. Right click on the formulation graph and select "Export to Excel"
    grafik
  2. Create new table formulation and import it from the exported Weibull formulation file
    grafik
  3. Configure your simulation and replace your Weibull formulation with the new table formulation
    Duloxetine_Table.zip

@AndreDlm FYI

@xixi-1995

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@xixi-1995 xixi-1995 commented Jan 9, 2020

@Yuri05 That's quite helpful!! Thank you very much!
I'm curious about why and will it be suit for situation similar, I will try more later~

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