Bioequivalence and Bioavailability Forum

❝ how to measure permeability of drug,

The following methods can be used to determine the permeability of a drug substance from the gastrointestinal tract:
(1) in vivo intestinal perfusion studies in humans;
(2) in vivo or in situ intestinal perfusion studies using suitable animal models;
(3) in vitro permeation studies using excised human or animal intestinal tissues; or
(4) in vitro permeation studies across a monolayer of cultured epithelial cells.

Dear compliance
Regulatory authorities still have some problems with biowaivers, especially if you provide in vitro data on permeability. Then you have to face a lot of questions. The demonstration of complete absorption in humans is preferred for BCS-based biowaiver applications. In most cases you will find information on permeability in scientific literature. If you are lucky it is mentioned in the originatorś SmPC or in the EPAR, then it can be regarded as public (approved) knowledge. Complete absorption is considered to be established where measured extent of absorption is ≥ 85 %. Complete absorption is generally related to high permeability.
I hope this helps.
Kind regards
Dan

Also make sure the Innovator IR product meets the in-vitro release spec that is suggested by the FDA guidance. Something like NLT 85% dissolved in 15 mins, otherwise you can't file a BCS class 1 biowaiver.