calc_vdist {httk} | R Documentation |
Calculate the volume of distribution for a one compartment model.
Description
This function predicts partition coefficients for all tissues using
predict_partitioning_schmitt
, then lumps them
into a single compartment.
Usage
calc_vdist(
chem.cas = NULL,
chem.name = NULL,
dtxsid = NULL,
parameters = NULL,
suppress.messages = FALSE,
adjusted.Funbound.plasma = TRUE,
species = "Human",
default.to.human = FALSE,
...
)
Arguments
chem.cas |
Either the CAS number or the chemical name must be specified when Funbound.plasma is not given in parameter list. |
chem.name |
Either the chemical name or the CAS number must be specified when Funbound.plasma is not given in parameter list. |
dtxsid |
EPA's DSSTox Structure ID (https://comptox.epa.gov/dashboard) the chemical must be identified by either CAS, name, or DTXSIDs |
parameters |
Parameters from parameterize_3comp, parameterize_pbtk or predict_partitioning_schmitt. |
suppress.messages |
Whether or not the output message is suppressed. |
adjusted.Funbound.plasma |
Uses Pearce et al. (2017) lipid binding adjustment for Funbound.plasma (which impacts partition coefficients) when set to TRUE (Default). |
species |
Species desired (either "Rat", "Rabbit", "Dog", "Mouse", or default "Human"). |
default.to.human |
Substitutes missing animal values with human values if true. |
... |
Additional parameters passed to parameterize function if parameters is NULL. |
Details
The effective volume of distribution is calculated by summing each tissues volume times it's partition coefficient relative to plasma. Plasma, and the paritioning into RBCs are also added to get the total volume of distribution in L/KG BW. Partition coefficients are calculated using Schmitt's (2008) method. When species is specified as rabbit, dog, or mouse, the function uses the appropriate physiological data(volumes and flows) but substitues human fraction unbound, partition coefficients, and intrinsic hepatic clearance.
Value
Volume of distribution |
Units of L/ kg BW. |
Author(s)
John Wambaugh and Robert Pearce
References
Schmitt W (2008). “General approach for the calculation of tissue to plasma partition coefficients.” Toxicology in vitro, 22(2), 457–467. doi:10.1016/j.tiv.2007.09.010.
Peyret T, Poulin P, Krishnan K (2010). “A unified algorithm for predicting partition coefficients for PBPK modeling of drugs and environmental chemicals.” Toxicology and applied pharmacology, 249(3), 197–207. doi:10.1016/j.taap.2010.09.010.
See Also
Examples
calc_vdist(chem.cas="80-05-7")
calc_vdist(chem.name="Bisphenol A")
calc_vdist(chem.name="Bisphenol A",species="Rat")
# Create a list of parameters (that you can potentially change):
p <- parameterize_schmitt(chem.name="propranolol")
# Need to use those parameters to predict partition coefficients:
PCs <- predict_partitioning_schmitt(parameters = p)
# Lump the tissues into a single volume of distribution
calc_vdist(parameters=c(p,PCs))
# Should be the same as chemical by name:
calc_vdist(chem.name="propranolol")
# Different ways to give the arguments:
calc_vdist(chem.cas="80-05-7")
params <- parameterize_schmitt(chem.name="triclosan")
params <- c(params, predict_partitioning_schmitt(parameters = params))
calc_vdist(parameters=params)
params <- parameterize_3comp(chem.name="triclosan")
calc_vdist(parameters=params)
params <- parameterize_pbtk(chem.name="triclosan")
calc_vdist(parameters=params)