Bioequivalence and Bioavailability Forum • TimeLow

TimeLow [🇷 for BE/BA]

posted by Astea – Russia, 2017-10-29 00:15 (2599 d 03:57 ago) – Posting: # 17938
Views: 24,702

Dear smart people!

Can anyone please suggest me an easy way of calculation T_50% early and late, T_75%, T_90% and similar parameters via Phoenix?

To this time I could only find this old thread deducated to Therapeutic Response Module. But following this module we can only get TimeLow, TimeHigh or TimeDuring in the output of pharmacokinetical parameters.

Imagine we have an ideal standard curve, than TimeLow=T_50%^early+T-T_50%^late, TimeDuring=T_50%^late-T_50%^early (here T is the total duration of observation). So it is impossible to get T_50%^ealy and T_50%^late separately from this data. To deal with it I had to delete data after T_max for calculating T_50%^early or before T_max for calculating T_50%^late.

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. 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. But this is not true for partial area calculation: for example, AUC_0-72 for subjects with missing t=72 value, Phoenix always do log interpolation even if we've choosen linear AUC calculation.

Returning to TimeLow calculation. 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

—
"Being in minority, even a minority of one, did not make you mad"

Complete thread:

Calculation of time above MIC Aceto81 2008-06-26 16:31 [🇷 for BE/BA]
- Calculation of time above MIC Helmut 2008-06-26 18:58
  - Calculation of time above MIC Aceto81 2008-06-26 21:50
    - Calculation of time above MIC Helmut 2008-06-27 00:18
    - Calculation of time above MIC Helmut 2008-06-29 02:24
      - Calculation of time above MIC Aceto81 2008-06-30 15:50
        
        Therapeutic Occupancy Time / MEC Helmut 2008-06-30 16:45
  - Time above MIC (WinNonlin 5.2.1) Helmut 2008-08-08 20:38
    - Time above MIC (WinNonlin 5.2.1) Aceto81 2008-08-12 09:56
      - Time above MIC (WinNonlin 5.2.1) Helmut 2008-08-12 12:32
        
        Time above MIC (R function) Aceto81 2008-08-13 11:19
        
        Time above MIC (R function) Helmut 2008-08-13 13:18
        
        Time above MIC (R function) Aceto81 2008-08-13 15:35
        
        Phoenix-WinNonlin 6.0 released 29 May 2009 SDavis 2009-06-04 10:55
        
        Phoenix-WinNonlin 6.0 Helmut 2009-06-04 11:57
        
        Phoenix-WinNonlin 6.0 - introductory webinars SDavis 2009-06-04 18:50
        
        Phoenix-WinNonlin 6.0 - introductory webinars Helmut 2009-06-04 23:40
    - TimeLowAstea 2017-10-28 22:15
      - PHX/WNL 8.0 vs. previous releases Helmut 2017-10-28 23:20
        
        PHX/WNL 8.0 vs. previous releases Astea 2017-10-28 23:49
      - Occupancy, Half Value Duration, Plateau Time in Phoenix/WinNonlin 8 Helmut 2017-10-30 13:18
        
        Occupancy, Half Value Duration, Plateau Time in Phoenix/WinNonlin 8 Astea 2017-10-31 01:12
        
        Intersections Helmut 2017-10-31 12:32
        
        nobody needs it... Astea 2017-10-31 18:24