run_npd_1cmpt_mm_oral: Run and evaluate a one-compartment oral model with...

In nlmixr2autoinit: Automatic Generation of Initial Estimates for Population Pharmacokinetic Modeling

Run and evaluate a one-compartment oral model with Michaelis-Menten kinetics

Description

Fits a one-compartment oral pharmacokinetic model with Michaelis-Menten elimination using a naive pooled data approach, and evaluates model performance using prediction error metrics.

Usage

run_npd_1cmpt_mm_oral(
  dat,
  est.method = "nls",
  input.ka = exp(1),
  input.vmax = exp(1),
  input.km = exp(1),
  input.cl = exp(1),
  input.vd = exp(1),
  input.add = 1,
  km_threshold = FALSE
)

Arguments

dat	A data frame containing raw time–concentration data in standard nlmixr2 format.
est.method	Estimation method used in nlmixr2. Defaults to "nls".
input.ka	Initial estimate for the absorption rate constant (ka). Defaults to exp(1), corresponding to a log-scale value of 1.
input.vmax	Initial estimate for the maximum metabolic rate (Vmax). Defaults to exp(1), corresponding to a log-scale value of 1.
input.km	Initial estimate for the Michaelis constant (Km). Defaults to exp(1), corresponding to a log-scale value of 1.
input.cl	Initial estimate for clearance (CL). Defaults to exp(1), corresponding to a log-scale value of 1. This value is used to derive initial Vmax and Km when km_threshold = TRUE.
input.vd	Initial estimate for volume of distribution (Vd). Defaults to exp(1), corresponding to a log-scale value of 1.
input.add	Additive error term. Defaults to 1.
km_threshold	Logical indicating whether initial Vmax and Km should be automatically adjusted based on observed maximum concentration and clearance. Defaults to FALSE.

Details

The function excludes dosing records (EVID == 2) prior to model fitting. When km_threshold = TRUE, initial estimates for Vmax and Km are derived using the observed maximum concentration and clearance. The model is then fitted using Fit_1cmpt_mm_oral, and prediction-based metrics are calculated to assess performance.

Value

A list containing the fitted parameter estimates and prediction error metrics.

Author(s)

Zhonghui Huang

See Also

Fit_1cmpt_mm_oral

Examples

  run_npd_1cmpt_mm_oral(
    dat = Oral_1CPTMM,
    input.ka = 1,
    input.vmax = 1000,
    input.km = 250,
    input.vd = 70
  )

nlmixr2autoinit documentation built on Nov. 14, 2025, 1:07 a.m.