Hi. I am running a very academic experiment using Phoenix NLME. I am trying to simulate several bioavailability scenarios from IV data. I developed a 2CM model for 2 subjects given drug X IV (naive pooled in Phoenix). I then used the estimated parameters for each of the 2 subjects (V, V2, CL, CL2) in the simulation object and added KA=0.8 as well as dosepoint(Aa, bioavail=(0.5)) to the simulation model. I then set the oral simulation to 1000 hrs, and 50 samples. I also used the IV parameters to simulate an IV study that ran to 1000 hrs, 50 samples. I then ran an NCA on the simulated oral and IV data. Using these data, I calculated absolute bioavailability. The curious thing is calculated F from the simulated data was 0.25 and NOT 0.5!! Why is this? Am I misusing the bioavail = (0.5)) in the dosepoint statement? Thanks! Cathrine.
Cathrine - it’s hard to tell without seeing your code/project? Can you share that? I am wondering if somehow you’ve accounted for F twice? Simon. UPDATE - Cathrine emailed me to say she sorted an error with the code out and is now getting the correct F. One of my colleagues says he did something similar; … put Fb into absorption like this: deriv(A1 = FbKaAa - ke*A1) and also had it in my dosepoint