Dear Certara Forum users,
I am modeling a long-acting release form and my absorption model can't fit very well. I am trying to use time-varying residual error model to fix my absorption phase.
My approach is like below: first create a categorical variable using absTime = if(Time__hr_<=24,1,0), then using two seperate proportional error terms for the absorption and distribution phase:
stparm(CMultStdev = tvCMultStdev*(absTime==0)+tvCMultStdev_absTime*(absTime==1))
This approach works, I am wondering is there a way that I can code directly in PML (without creating the dummy variable absTime), maybe use if else statement?
Thanks in advance,
CTM, University of Maryland