Run this command in R console to install necessary packages:
install.packages("tidyverse", "mrgsolve", "mrgsim.sa", "nloptr", "numDeriv", "kableExtra",
"PKNCA", "cowplot", "future", "mrgsim.parallel", "shiny", "here", "knitr", "lattice", "patchwork", "FME", "sensobol", "data.table")
To install PBPKToolkit use: install.packages("https://github.com/aelmokadem/PBPKToolkit.git")