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nlmixrdevelopment / nlmixr

nlmixr: an R package for population PKPD modeling
https://nlmixrdevelopment.github.io/nlmixr/
GNU General Public License v2.0
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mixed (zero and first order) absorption model #511

Closed harishkaushikbugworks closed 3 years ago

harishkaushikbugworks commented 3 years ago

Hello Matt,

Iam trying to build mixed (zero and first order) absorption model of donepezil from transdermal patch application in nlmixr I need your help in writing code for modelling these kind of profiles

Iam Choi2015_Article_Poppk of donepezil patch.pdf attaching the paper, iam referring to

Regards HKK

mattfidler commented 3 years ago

Typically this is performed by splitting the dose in the dataset into two groups:

  1. Group one is to the central compartment; In nlmixr this can be the name of the compartment like central or the compartment number like 1. The dose is the total amount of the dose the system.
  2. Group two is to the depot compartment; In nlmixr this can be the name of the compartment like depot or the compartment number like 2.

In the model you would specify the depot compartment like:

model({
d/dt(depot) <- -ka*depot
d/dt(central) <- ka*depot - kel*central
f(central) <- fc
f(depot) <- 1 - fc
})

I haven't read the paper, so you should adjust the model to match the paper (ie number of compartments, maybe there is a PD component etc)