Remove zero-order absorption from a model

Removes the modeled duration on the central compartment, leaving the dose as an intravenous bolus input. The duration variable is taken from the right hand side of the dur(central) line: when it is defined by an assignment in the model (the tk0 <- exp(ltk0) added by [addZeroOrderAbs()] or the durCentral added by [addDur()]) the variable and its initial estimate are dropped too; a bare estimated parameter that is not used elsewhere in the model is dropped from the initial estimates. First-order absorption can be restored with [addDepot()].

Usage

removeZeroOrderAbs(ui, central = "central")

Arguments

ui

The model as a function (or something convertible to an rxUi object)

central

central compartment name

Value

a model where the zero-order absorption is removed

See also

Other absorption: addSecondAbsorption(), addTransit(), addWeibullAbs(), addZeroOrderAbs(), convertAbsForceLongerDelay(), convertAbsSequential(), removeTransit()

Author

Matthew L. Fidler

Examples

readModelDb("PK_1cmt_des") |> addZeroOrderAbs() |> removeZeroOrderAbs()
#>  
#>  
#> Warning: 'depot' removed for zero-order absorption model
#>  ── rxode2-based free-form 1-cmt ODE model ────────────────────────────────────── 
#>  ── Initalization: ──  
#> Fixed Effects ($theta): 
#>    lcl    lvc propSd 
#>   1.00   3.45   0.50 
#> 
#> States ($state or $stateDf): 
#>   Compartment Number Compartment Name
#> 1                  1          central
#>  ── Model (Normalized Syntax): ── 
#> function() {
#>     compartmentData <- list(depot = list(analyte = "drug", units = NA_character_, 
#>         specimen = "administration site", verified = FALSE), 
#>         central = list(analyte = "drug", units = NA_character_, 
#>             specimen = "plasma", verified = FALSE))
#>     dosing <- c("central", "depot")
#>     reference <- "nlmixr2lib template"
#>     units <- list(time = "time_unit", dosing = "dose_unit", concentration = "conc_unit/vol_unit")
#>     ini({
#>         lcl <- 1
#>         label("Clearance (CL)")
#>         lvc <- 3.45
#>         label("Central volume of distribution (V)")
#>         propSd <- c(0, 0.5)
#>         label("Proportional residual error (fraction)")
#>     })
#>     model({
#>         cl <- exp(lcl)
#>         vc <- exp(lvc)
#>         kel <- cl/vc
#>         d/dt(central) <- -kel * central
#>         Cc <- central/vc
#>         Cc ~ prop(propSd)
#>     })
#> }