PHX8: Half Value Duration (HVD) and Plateau Time (T75%)

Phoenix Certara Forums Phoenix WNL basics
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Dear all,

in previous releases of PHX/WNL the intersection of the profile with a fixed value was always performed by linear interpolation (increasing concentrations) and by log/linear interpolation (decreasing concentration) – which IMHO, is the method of choice.
This lead to confusion in the past since this method was independent from the selected AUC calculation. Since v8.0 the method observes the chosen AUC-rule.
Calculating the Occupancy Time (time interval where concentrations are at least some limiting value, e.g., the MIC) is trivial. However, the Half Value Duration (HVD, interval where C ≥ 50% Cmax) or the Plateau Time (t75%, interval where C ≥ 75% Cmax) needs two steps.

  1. Get the subject’s Cmax and calculate the required fraction(s).
  2. In the final NCA > Therapeutic Response > map the calculated fraction to Lower and Cmax to Upper.
    Half Value Duration and Plateau Time.phxproj (1.18 MB)
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Thanks for your feedback as always Helmut. Your comments have been added to an existing issue QC16467.

Simon

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PD metrics for Ciprofloxacin.pdf (63.4 KB)