USEPA / CompTox-ExpoCast-httk

The R package "httk" provides free, open-source data and models for toxicokinetics. The models are designed to use chemical-specific in vitro (animal free) measurements. The predictions can be used for traditional dosimetry as well as in vivo-in vitro extrapolation (IVIVE). This repository is for reporting bugs and contributing enhancements.
https://cran.r-project.org/package=httk
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Generic question #5

Closed PARODBE closed 2 years ago

PARODBE commented 2 years ago

Hi!

Nice to meet you, and I have a generic question. If you want incorporate toxicokinetic information to qsar models, I think that this tool is very useful, but in your opinion which could be the most interesting variables? Kel,Vd,Css,Cl,Fub? And in this case are there a function? because when I am running a loop for calc_tkstats for all compounds, I am obtaining:

Error in parameterize_pbtk(chem.cas = NULL, chem.name = c("2,2-bis(4-hydroxyphenyl)-1,1,1-trichloroethane (hpte)", : Missing metabolic clearance data for given species.

Thanks! Pablo

jfwambaugh commented 2 years ago

Depending on what you're trying to predict Css might capture most of what you want, since Css is proportional to 1/CLtot, and CLtot = Vd*kelim (for a 1 compartment model).

When you loop you want to use the get_cheminfo() function to identify the chemicals for which a given model will work, like get_cheminfo(model="1compartment").

So to get all the 1compartment parameters use this:

chem.descs <- NULL for (this.chem in get_cheminfo(model="1compartment")) chem.descs <- rbind(chem.descs,c(this.chem,unlist(parameterize_1comp(chem.cas=this.chem))))

To get just Css use: chem.descs <- NULL for (this.chem in get_cheminfo(model="1compartment")) chem.descs<- rbind(chem.descs,c(this.chem,calc_analytic_css(chem.cas=this.chem,model="1compartment")))

The main other descriptor I might want to know is ionization state in plasma (pH=7.4): chem.descs <- NULL for (this.chem in get_cheminfo(model="1compartment")) chem.descs<- rbind(chem.descs,c(this.chem,calc_ionization(chem.cas=this.chem, pH=7.4)))

PARODBE commented 2 years ago

Uooh thank you so much!!! Very useful!!