Pint - Peff

[fsimon92]

Dear all,

I have a question regarding Specific intestinal permeability order of magnitude.

After a small literature review of PK-sim published models, the order of magnitude of Pint is usually between 10-7 and 10-5 cm/s (broad range), which is 2-3 orders of magnitude different from human intestinal effective permeability (Peff).

I'm wondering if anyone knows from which parameter/scaling factor this could come from ?

I have identified the following ones as potential clue but not certain:

• In the effective surface area definition in Mobi there is this "Effective surface area enhancement factor"

Is it something related to microvili amplification factor as in Eq (1) from the following publication or something else ? (https://doi.org/10.1002/jps.22726)

• In the drug absorption rate definition from lumen to mucosa there are two factors "Pint_trans_lum_cell_factor" and "Pint_trans_cell_lum_factor", do you know for what purpose ?

I know there have been some discussions on this topic (such as the one below) but this is still not completely clear to me.
Extremely low Specific intestinal permeability values calculated with PK-Sim · Issue #23 · Open-Systems-Pharmacology/Forum

Thank you for your help.

Best regards,
Florian