Can I use RxODE2 to simulate multiple doses in population?

[WXX155367]

Hi guys. I would like to ask if I can use RxODE to simulate multiple dose at the same time in population simulation? I mean, the dosage increases in a regular way, for example from 100mg to 500mg. I want to simulate different blood drug concentrations in the same population at 100mg, 200mg, 300mg, 400mg, and 500mg. Can I write code in the event table to include these dosages?

[mattfidler]

Yes you can, something like the following would work:

e <- et(amt=100) %>% et(amt=200, time=24) %>% et(amt=300, time=48) %>% et(seq(1:48)) %>% et(id=1:24)

[mattfidler]

Well, while it is legal, I'm unsure why you would want to do this, since it is equivalent to a dose of 600 (100 + 200 + 300) at time zero. You could simply use e <- et(amt=600) %>% et(seq(1:48)) %>% et(id=1:24)

If you are trying to dose in different cohorts that is a bit different, you would need to use something like:

e1 <- et(amt=100) %>% et(1:24) %>% et(id=1:10)
e2 <- et(amt=200) %>% et(1:24) %>% et(id=11:20)
e3 <- et(amt=300) %>% et(1:24) %>% et(id=21:30)
e <- rbind(e1, e2, e3)

[WXX155367]

Thanks thanks. Because I want to simulate the different doses for the same population at the same time. I was wondering whether I can write a code which can include that idea and save time to do simulation.

[mattfidler]

Yes, but you would have use the approach where you have different subject numbers for each simulation, as above.

Then you would:

• Extract your parameters
• Duplicate your pararmeters (one per subject)
• Solve the full dataset with the duplicated ETAs.

Then the different doses would be solved in the same population.

[mattfidler]

Another approach is to use the same subject ids and a reset, for example:

e1 <- et(amt=100) %>% et(1:24) %>% et(id=1:10)
e2 <- et(amt=200, evid=4) %>% et(1:24) %>% et(id=11:20)
e3 <- et(amt=300, evid=4) %>% et(1:24) %>% et(id=21:30)
e <- rbind(e1, e2, e3)

This may work, I'm unsure if you need to setup your dataset differently

You need the dataset to have an individual time c(0 .. X) then reset with c(0..x) so I'm unsure if the above will work, but if it is constructed for one individual and then duplicated for each individual it could work that way.

[WXX155367]

Thanks for your reply. I got it. 🙏