Interface with nlmixr (estimation)

[KyleBarrett]

Hi Ron,
I was wondering how well PKPDsim interfaces with nlmixr. I noticed your pkpdsim_to_nlmix() function accurately creates an nlmixr ui model to be fitted, given a simple model. PKPDsim provides more flexibility in model specification, such as allowing the specification of time varying covariates. I myself am having an issue just with creating fixed covariates with nlmixr while using the saem estimation method (this is a known issue with nlmixr and saem). I am assuming if the functionality was not implemented in nlmixr, but was with PKPDsim, the model will not translate well. I was hoping you could confirm or deny this, and if that is the case, have you utilized any other R packages for estimation that work well with PKPDsim?