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Estimate starting parameters using PKNCA

Source: R/pknca.R
nlmixr2Est.pknca.Rd

Estimate starting parameters using PKNCA

Usage

# S3 method for class 'pknca'
nlmixr2Est(env, ...)

Arguments

env

Environment for the nlmixr2 estimation routines.

This needs to have:

- rxode2 ui object in `$ui`

- data to fit in the estimation routine in `$data`

- control for the estimation routine's control options in `$ui`

...

Other arguments provided to `nlmixr2Est()` provided for flexibility but not currently used inside nlmixr

Value

A model with updated starting parameters. In the model a new element named "nca" will be available which includes the PKNCA results used for the calculation.

Details

Parameters are estimated as follows:

  • ka 4 half-lives to Tmax but not higher than 3: log(2)/(tmax/4)

  • vc Inverse of dose-normalized Cmax

  • cl Estimated as the median clearance

  • vp,vp22- and 4-fold the vc, respectively by default, controlled by the vpMult and vp2Mult arguments to pkncaControl

  • q,q2 0.5- and 0.25-fold the cl, respectively by default, controlled by the qMult and q2Mult arguments to pkncaControl

The bounds for the parameter estimates are set to 10% of the first percentile and 10 times the 99th percentile. (For ka, the lower bound is set to the lower of 10% of the first percentile or 0.03 and the upper bound is not modified from 10 times the 99th percentile.)

Parameter estimation methods may be changed in a future version.