PHX/WNL 8.0 vs. previous releases [R for BE/BA]

posted by Helmut Homepage – Vienna, Austria, 2017-10-28 23:20 (1501 d 13:19 ago) – Posting: # 17939
Views: 20,446

Hi Astea,

» Can anyone please suggest me an easy way of calculation T50% early and late, T75%, T90% and similar parameters via Phoenix?

Maybe later. ;-)

» By the way, in this old thread as well as in this it was written that Phoenix approximates the decreasing part with log-transformation independetly of the rule choosen for AUC.

Although not described in the User’s Guide, correct.

» Now it seemed to be changed, and the actual form of approximation depends on the rule for AUC, so it can be linear as well as log-linear.

Correct since the current release v8.0 (formulas (6) and (7) on p53 of the User’s Guide).

» But this is not true for partial area calculation: for example, AUC0-72 for subjects with missing t=72 value, Phoenix always do log interpolation even if we've choosen linear AUC calculation.

Like in previous versions (though I didn’t check it)-

» I am also puzzled why for the following dataset we get TimeLow=18 if Lower limit is choosen to be 3? Because if we substract 4 from all time points we'll get 16... (linear interpolation was selected)
»  t | C
» ---+---
»  4 | 6
»  6 | 4
»  8 | 3
» 10 | 2
» 12 | 0
» 24 | 0

Since your data set doesn’t contain a concentration at t=0, it is extrapolated (see the core output). The method depends on the Dose Options. For Extravascular we get C=0 and for IV Bolus C=13.5. Then I got these results for TimeLow in the releases of Phoenix/WinNonlin I have on my machine:

Dose Options  6.3  6.4  7.0  8.0
Extravascular  28   28   28   18
IV Bolus       31   31   31   16

I will explore it further…

Dif-tor heh smusma 🖖
Helmut Schütz

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