Bioequivalence and Bioavailability Forum

Thanks for your responses Helmut.

❝ If you mean by variability the variances (and not the CVs), you are almost there.

Yes - variances - I only use CVs to help explain the magnitude of the variability.

❝ OK, this is one of the often quoted ‘rules of thumb’ which have no statistical background. If it worked in your experience, you have been lucky.

Please explain what you mean by "lucky"? In your experience do you find this not to be true more times than not?

❝ A justification of any ‘rule’ would a require a sufficiently high correlation between intra- and inter-subject variability. What I have seen in my studies (checked ~150 until I got bored) is R² of 0.5…

I will have to take a look at this. R² = 0.5 is not very good. I have worked on well over 500 BE type studies so I have a lot of data.

❝ Too bad. Would have been nice to dissect it.

Still looking – if I find it, I will share it with you.

❝ Again: Lucky you!

Here again, please explain what you mean by "lucky"?

❝ Not necessarily the drug, but it might be the formulation as well. No very uncommon for PPIs.

OK - I guess I should have been more specific and said treatment regimen - to me this means the drug, formulation, whatever else goes along with it. IMO - if the within > between, you have no control over exposure in any given patient and this is bad. Thus, big problems and more than likely, a dead "treatment regimen".

thanks again!