Bioequivalence and Bioavailability Forum • Confusing

Confusing [Regulatives / Guidelines]

posted by Helmut – Vienna, Austria, 2019-03-02 16:37 (2143 d 11:28 ago) – Posting: # 19985
Views: 6,480

Hi John,

❝ Here is the exact wordings from the table (if that makes any difference to what I posted). Note that the summary table also presented +/- Westlake 95% CI..

❝

❝ Cmax(n=24):

❝ Detectable differences(%)=13.28

“Detectable difference” stinks of the FDA’s 80/20 rule (at least 80% post hoc power to detect a 20% difference). Was applied till 1992. IMHO, since 13.28% < 20%, C_max failed.

❝ T/R Ratio=93.86%

❝ +/- Westlake 95% CI=20.12%

Why 95%? However, Westlake’s CI is an information sink (example). By fiddling around with the t-values his CI is always symmetric around 100%. He suspected that clinicians are not comfortable with a CI which is asymmetric (see this post). As a side effect the T/R-ratio should not be given.

❝ One sided t-test 90% CI:Lower limit= -18.33%, Upper Limit= -6.36%

Here’s the other way ’round. Should be 95%.

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Helmut Schütz

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Complete thread:

History lessons - FDA BE 90% CI jag009 2019-02-25 22:03 [Regulatives / Guidelines]
- History lessons - FDA BE 90% CI nobody 2019-02-25 22:39
  - History lessons - FDA BE 90% CI Helmut 2019-02-26 00:44
    - History lessons - FDA BE 90% CI jag009 2019-02-26 15:19
      - History lessons - FDA BE 90% CI nobody 2019-02-26 16:07
      - Strange result Helmut 2019-02-28 12:03
        
        Strange result nobody 2019-03-01 08:50
        
        Pandora's box? jag009 2019-03-01 17:40
        
        ConfusingHelmut 2019-03-02 15:37
        
        Strange result jag009 2019-03-01 17:44
        
        Transformation, acceptance range Helmut 2019-03-02 15:09
        
        Transformation, acceptance range nobody 2019-03-02 16:42