Bioequivalence and Bioavailability Forum

Dear Dan, Srinivasu & all!

❝ I totally understand Srinivasu. From the point of view of a generic company it is very frustrating to see that comparable dissolution does not mean bioequivalence between test and reference.

I do understand this desire too. Sorry if I was too harsh in my reaction, but the question scratched the basics.

❝ In case of a high soluble drug with a good bioavailability there should be no problem but in other cases we can not predict the outcome.

Even then it might be problematic. Imagine we perform not only dissolution testing, but opt for a model of the upper GIT (like TNO’s TIM-1). It’s telling that TNO talks about ‘bioaccessability’ – not bioavailability. If the drug is subjected to presystemic metabolism or affected by active transport any in vitro model will fail.

❝ Therefore we try to find some in vitro test which would make the in vivo testing more predictable.

You are not alone – everybody does.
Now for some heresy: How do you assess the predictability of you in vitro test without in vivo data? Is f₂>50 in three pHs enough? Would you go for physiological media (FASSIF/FESSIF)?