A methodology for solving physiologically based pharmacokinetic models without the use of simulation softwares

The objective of the present study was to develop and validate a methodology for solving physiologically based pharmacokinetic (PBPK) models without the use of simulation software. The approach involves keying the parameter values and model equations into Microsoft Excel(R) spreadsheets, and conducting simulations by solving the model equations according to Euler's method of numerical integration. This approach was applied to simulate the pharmacokinetics of styrene in rats exposed to 80 and 600 ppm for 6 h. The simulation results were plotted along with experimental data using the regular graphic features available in Excel(R), and validated by comparing them with simulation results obtained using a commercially available software (Advanced Continuous Simulation Language, ACSL(R)). The simulations obtained with ACSL(R) and Excel(R), in general, differed by < 1%. The methodology developed in the present study should help informed individuals understand and solve PBPK models, without having to use 'black-box' kind of computer programs and simulation softwares.