httk (version 1.8)

predict_partitioning_schmitt: Predict partition coefficients using the method from Schmitt (2008).

Description

This function implements the method from Schmitt (2008) in predicting the tissue to unbound plasma partition coefficients from for the tissues contained in the tissue.data table.

Usage

predict_partitioning_schmitt(chem.name=NULL,chem.cas=NULL,species="Human",
                             default.to.human=F,parameters=NULL,
                             adjusted.Funbound.plasma=T, regression=T,
                             regression.list=c('brain','adipose','gut','heart','kidney',
                                        'liver','lung','muscle','skin','spleen','bone'),
                             tissues=NULL)

Arguments

chem.name

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

chem.cas

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

species

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

default.to.human

Substitutes missing animal values with human values if true (hepatic intrinsic clearance or fraction of unbound plasma).

parameters

Chemical parameters from the parameterize_schmitt function, overrides chem.name and chem.cas.

adjusted.Funbound.plasma

Whether or not to use Funbound.plasma adjustment.

regression

Whether or not to use the regressions. Regressions are used by default.

regression.list

Tissues to use regressions on.

tissues

Vector of desired partition coefficients. Returns all by default.

Value

Returns tissue to unbound plasma partition coefficients for each tissue.

Details

A separate regression is used when adjusted.Funbound.plasma is FALSE.

A regression is used for membrane affinity when not provided. The regressions for correcting each tissue are performed on tissue plasma partition coefficients (Ktissue2pu * Funbound.plasma) calculated with the corrected Funbound.plasma value and divided by this value to get Ktissue2pu. Thus the regressions should be used with the corrected Funbound.plasma.

The red blood cell regression can be used but is not by default because of the span of the data used, reducing confidence in the regression for higher and lower predicted values.

Human tissue volumes are used for species other than Rat.

Examples

# NOT RUN {
predict_partitioning_schmitt(chem.name='ibuprofen',regression=FALSE)
# }