calc_half_life {httk}

Calculates the half-life for a one compartment model.

Description

This function calculates the half life from the three compartment steady state model where elimination is entirely due to metabolism by the liver and glomerular filtration in the kidneys.

Usage

calc_half_life(
  chem.cas = NULL,
  chem.name = NULL,
  dtxsid = NULL,
  parameters = NULL,
  species = "Human",
  suppress.messages = TRUE,
  default.to.human = FALSE,
  restrictive.clearance = TRUE,
  adjusted.Funbound.plasma = TRUE,
  regression = TRUE,
  well.stirred.correction = TRUE,
  clint.pvalue.threshold = 0.05,
  minimum.Funbound.plasma = 1e-04
)

Arguments

chem.cas

Either the cas number or the chemical name must be specified.

chem.name

Either the chemical name or the cas number must be specified.

dtxsid

EPA's 'DSSTox Structure ID (https://comptox.epa.gov/dashboard) the chemical must be identified by either CAS, name, or DTXSIDs

parameters

Chemical parameters from parameterize_steadystate or 1compartment function, overrides chem.name and chem.cas.

species

Species desired (either "Rat", "Rabbit", "Dog", "Mouse", or default "Human").

suppress.messages

Whether or not the output message is suppressed.

default.to.human

Substitutes missing animal values with human values if true.

restrictive.clearance

In calculating elimination rate, protein binding is not taken into account (set to 1) in liver clearance if FALSE.

adjusted.Funbound.plasma

Uses adjusted Funbound.plasma when set to TRUE along with partition coefficients calculated with this value.

regression

Whether or not to use the regressions in calculating partition coefficients.

well.stirred.correction

Uses correction in calculation of hepatic clearance for -stirred model if TRUE. This assumes clearance relative to amount unbound in whole blood instead of plasma, but converted to use with plasma concentration.

clint.pvalue.threshold

Hepatic clearance for chemicals where the in vitro clearance assay result has a p-values greater than the threshold are set to zero.

minimum.Funbound.plasma

Monte Carlo draws less than this value are set equal to this value (default is 0.0001 – half the lowest measured Fup in our dataset).

Details

Half life is calculated by dividing the natural-log of 2 by the elimination rate from the one compartment model.

Value

Half life

Units of h.

Author(s)

Sarah E. Davidson

See Also

[calc_elimination_rate()] for the elimination rate calculation

Examples

calc_half_life(chem.name="Bisphenol A")
calc_half_life(chem.name="Bisphenol A",species="Rat")
calc_half_life(chem.cas="80-05-7")