You are here:
R Package httk
Citation:
Wambaugh, J., R. Pearce, C. Strope, Woodrow Setzer, AND N. Sipes. R Package httk. U.S. Environmental Protection Agency, Washington, DC, 2019.
Impact/Purpose:
Open source software package for upload to the public Comprehensive R Archive Network (CRAN) server.
Description:
Thousands of chemicals have been pro?led by high-throughput screening programs such as ToxCast and Tox21; these chemicals are tested in part because most of them have limited or no data on hazard, exposure, or toxicokinetics. Toxicokinetic models aid in predicting tissue concentrations resulting from chemical exposure. The "reverse dosimetry" approach has been used to predict exposure doses su?cient to cause tissue concentrations that have been identi?ed as bioactive by high-throughput screening. We have created four empirical and physiologically-based toxicokinetic models within a new R software package, httk. These models are designed to be parameterized using high-throughput in vitro data (the fraction of chemical unbound to plasma and the hepatic clearance), as well as structure-derived physicochemical properties and species-specifi?c physiological data for the calculation of partition coefficients, blood flows, and tissue volumes. The package contains tools for Monte Carlo sampling and reverse dosimetry along with functions that solve for concentration vs. time curves, steady state concentrations, and other toxicokinetic summary statistics. The package can currently make predictions for 389 chemicals in humans, mice, dogs, and rabbits (human chemical values are substituted for these three species), including 76 pharmaceuticals and 282 ToxCast chemicals, and 65 in rats. It is structured to be augmented with additional chemical data as they become available.
