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RegisterExcluding time points for lambdaZ [RSABE / ABEL]
Dear Helmut, dear FI!
In this post I had claimed "I never have seen deficiency questions concerning the fit of the terminal phase of concentration time courses in my ~30 years career. Even if the 'fit' was done with only 2 points".
Say never never.
Quite recently I got:
The questioned cases had in common that the last measured concentration was increasing compared to the preceding ones and doesn't fit into the linear part for the log-linear regression. To not grossly overestimate the terminal half-life in such situations it is my standard operation to act according to Helmut's first option above.
Seems some regulators opinion do not match mine.
❝ ❝ What if one concentration looks to be an analytical mistake(?), that confounds t1/2 in such a way that the slope increases...?
❝ ...
❝ Other options (?):
- Exclude the suspect value from the estimation of λz. Keep it in the calculation of AUCt and base the calculation of AUC∞ not on Ct, but on its estimate (in Phoenix/WinNonlin’s terminology:
AUCinfpredinstead ofAUCinfobs).❝
- ...
In this post I had claimed "I never have seen deficiency questions concerning the fit of the terminal phase of concentration time courses in my ~30 years career. Even if the 'fit' was done with only 2 points".
Say never never.
Quite recently I got:
… The applicant should justify the calculation of the terminal rate constant for patient #xxx, reference/r.1, patient #yyy, test/r.2 …
(It was a replicate BE study in patients).The questioned cases had in common that the last measured concentration was increasing compared to the preceding ones and doesn't fit into the linear part for the log-linear regression. To not grossly overestimate the terminal half-life in such situations it is my standard operation to act according to Helmut's first option above.
Seems some regulators opinion do not match mine.
—
Regards,
Detlew
Regards,
Detlew
Complete thread:
- SAS error in 3 way ref replicate study AB 2012-05-04 15:13 [RSABE / ABEL]
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- SAS error in 3 way ref replicate study jag009 2012-05-04 15:36
- SAS error in 3 way ref replicate study AB 2012-05-05 06:45
- FDA's ABE code and partial replicate design d_labes 2012-05-06 10:10
- Arbitrary (and unjustified) cut-off of r² Helmut 2012-05-06 13:29
- Anscombe quartet d_labes 2012-05-07 08:48
- Anscombe quartet in R Helmut 2012-05-07 11:15
- Anscombe quartet in R AB 2012-05-07 12:07
- Anscombe quartet in R Helmut 2012-05-07 11:15
- Arbitrary (and unjustified) cut-off of r² FI 2012-10-08 10:39
- Predominant half life; exclusions Helmut 2012-10-08 13:45
- Excluding time points for lambdaZd_labes 2012-10-09 09:33
- Analytical variability Helmut 2012-10-09 14:09
- Answer machine d_labes 2012-10-09 15:15
- Well done! Helmut 2012-10-09 19:43
- Answer machine d_labes 2012-10-09 15:15
- Analytical variability Helmut 2012-10-09 14:09
- Excluding time points for lambdaZd_labes 2012-10-09 09:33
- Predominant half life; exclusions Helmut 2012-10-08 13:45
- Anscombe quartet d_labes 2012-05-07 08:48
- Arbitrary (and unjustified) cut-off of r² Helmut 2012-05-06 13:29
- SAS error in 3 way ref replicate study jag009 2012-05-04 15:36
Ing. Helmut Schütz