ED80

Phoenix Certara Forums Phoenix WNL basics
1

Hi

I am performing a PK/PD analysis using Phoenix 7.0 and have fitted a Sigmoidal Emax model with Dose vs PD effect and would like to also have an estimate of the EC / ED80, as well as the EC / ED50 that is already presented as a parameter, for predicting a range of doses. Can anybody help with adding this?

Thanks

Jon

2

Hi Jon - if you search the forum you’ll find the related time about EC90;

https://support.certara.com/forums/topic/1034-qa-from-lesson-12-sigmoidal-response-models/?hl=ec90

It states that …

If EC50 and n are known, a general equation to calculate ECF, where F is any percentage, is

ECF = ((F/100-F)^(1/n)*EC50))

So I think for your ED80, add the following line to the code to calculate from the textual sigmoidal Hill Emax model:

secondary(ED80 = ((80/(100-80))^(1/n) * EC50))

The ED80 calculated from this equation will appear in the output worksheet named Secondary.

Simon