2 replies to this topic

[Helmut Schütz]

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% C_max) or the Plateau Time (t_75%, interval where C ≥ 75% C_max) needs two steps.

1. Get the subject’s C_max and calculate the required fraction(s).
2. In the final NCA > Therapeutic Response > map the calculated fraction to Lower and Cmax to Upper.

It is not possible to calculate HVD and t_75% simultaneously. If you need both, run two NCAs and join their results.
 Half Value Duration and Plateau Time.phxproj   1.18MB   479 downloads

[Simon Davis]

Thanks for your feedback as always Helmut.  Your comments have been added to an existing issue QC16467.

 

 Simon

[Angus McLean]

 PD metrics for Ciprofloxacin.pdf   63.35KB   706 downloadsHelmut thank you for this stimulating  post:  when I look at this work I think in the direction anti-infective metrics for efficacy like for example Cmax/MIC etc. that can be applied to drugs like ciprofloxacin.  I attach a paper on Cipro.