Leads to a (pseudo-) period effect [Bioanalytics]

posted by Helmut Homepage – Vienna, Austria, 2019-09-19 15:33  – Posting: # 20619
Views: 1,531

Dear Ravuri and dshah,

I’m the last person to stick to guidelines (if scientifically doubtful) but the EMA’s, FDA’, and ICH’s are pretty good ones.

» Can the study samples of same subject in more than single run for cross over design can be analysed i'e analysis of P1 samples and P2 samples can be carried out separately in two different runs? If yes, how it need to be justify to regulatory?

As always the guidance states “should be” not “have to be”. OK, why do you think it is necessary to analyze periods in different batches? Long washout and problems with stability? More information please.

» If we choose different run, then there is high possibility of getting slight different calibration curve equation and thus finally concentration for the unknown samples.

Correct so far.

» Thus it could have direct impact on BE.

Here you err, IMHO. Don’t get me wrong, I would analyze all samples in the same batch if ever possible as well (even staggered sampling times – not one period after the other). However, if Ravuri would have different responses in his approach, they would show up in the ANOVA as a period effect – which is automatically corrected for and thus not relevant in assessing the treatment effect.

Cheers,
Helmut Schütz
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