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Open-Systems-Pharmacology / Pregnancy-Models

Physiologically Based Pharmacokinetic Models for Pregnant Women
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Passive Diffusion Placenta Barrier #6

Closed Chrizsly closed 3 years ago

Chrizsly commented 4 years ago

Dear all,

Following the tutorial (https://doi.org/10.1002/psp4.12300) on how to extend a generic PBPK model to include pregnant females, I encountered what I believe is a wrongful implementation of the equation describing the passive diffusion of a molecule across the placental barrier. More specifically, in MoBi, after loading a PK-Sim file and adding the spatial and passive transport building blocks, the equation that is implemented looks like this:

image

However, the equation, like all other passive diffusion equations should look like this: image

Basically, the fraction unbound is applied to both terms and the partition coefficient is divided rather than multiplied. I would appreciate any feedback on this very much. Thanks and best,

Christian

msevestre commented 4 years ago

@AndreDlm . Any comment on this?

PavelBal commented 4 years ago

The only problem that I see is that K_cell_pls should actually be K_cell_wat - so "Partitioning coefficient water/container" rather than "Plasma/container". Otherwise the original equation looks correct.

PavelBal commented 4 years ago

And since Partition coefficient (intracellular/water) is nothing else than fu / K_cell_pls, @Chrizsly is right.

AndreDlm commented 4 years ago

yes I confirm that, thanks @PavelBal for commenting quickly

Chrizsly commented 3 years ago

Ok, thanks for the clarification. Would be good if this could be updated in the next version or so. Issue resolved now.

msevestre commented 3 years ago

Let's keep this one open since it's a bug;-)