httk (version 2.7.0)

calc_clearance_frac: Calculate the fractional contributions to total clearance

Description

Steady-state clearance is a function of multiple processes. For example, meabolism in the liver and glomerular filtration in the kidney. This function takes a list of parameters potentially impacting total clearance and iteratively sets all but one of the paramters to zero. This allows calculation of the fration of total clearance driven by that parameter.

Usage

calc_clearance_frac(
  fraction.params = c("Clint", "Qgfrc"),
  chem.cas = NULL,
  chem.name = NULL,
  dtxsid = NULL,
  parameters = NULL,
  species = "human",
  default.to.human = FALSE,
  suppress.messages = FALSE,
  model = "3compartmentss",
  restrictive.clearance = TRUE,
  parameterize.args = list(),
  analytic_css.args = list()
)

Value

A numeric fraction unpbound in plasma between zero and one

Arguments

fraction.params

A vector of character strings identifying the parameters whose fractional contributions are to be calculated. Defaults to 'Qfgr' and 'Qtotal.liverc'.

chem.cas

Chemical Abstract Services Registry Number (CAS-RN) -- if parameters is not specified then the chemical must be identified by either CAS, name, or DTXISD

chem.name

Chemical name (spaces and capitalization ignored) -- if parameters is not specified then the chemical must be identified by either CAS, name, or DTXISD

dtxsid

EPA's 'DSSTox Structure ID (https://comptox.epa.gov/dashboard) -- if parameters is not specified then the chemical must be identified by either CAS, name, or DTXSIDs

parameters

Parameters from the appropriate parameterization function for the model indicated by argument model

species

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

default.to.human

(Logical) Substitutes missing rat values with human values if TRUE. (Not applicable for `calc_fabs.oral`.) (Defaults to `FALSE`.)

suppress.messages

Whether or not the output message is suppressed.

model

Model used in calculation, for example'pbtk' for the multiple compartment model,'3compartment' for the three compartment model, and '1compartment' for the one compartment model. Defaults to '3compartmentss'.

restrictive.clearance

Protein binding not taken into account (set to 1) in liver clearance if FALSE.

parameterize.args

Named list of any additional arguments passed to model parameterization function (other than the already-named arguments). Default `list()` to pass no additional arguments.

analytic_css.args

Arguments to analytical Css function

Author

John Wambaugh

Examples

# 3compartmentss model:
calc_clearance_frac(chem.name="bisphenola")

# pbtk model:
calc_clearance_frac(chem.name="bisphenola",
                    model="pbtk",
                    fraction.params=c("Qgfrc","Clmetabolismc"))

# \donttest{
# A model with exhalation:
# sumclearances model:
calc_clearance_frac(chem.name="bisphenola",
                    model="sumclearances",
                    fraction.params=c("Clint","Qgfrc","Qalvc"))

calc_clearance_frac(chem.name="toluene",
                    model="sumclearances",
                    fraction.params=c("Clint","Qgfrc","Qalvc"))
                      
# 3comp2 model:
calc_clearance_frac(chem.name="toluene",
                    model="3compartment2",
                    fraction.params=c("Clmetabolismc","Qgfrc","Qalvc"))
# }