SimBiology® software extends the MATLAB® computing environment for analyzing pharmacokinetic (PK) data using models. The software lets you do the following:
Create models — Use a model construction wizard. Alternatively, extend any model with pharmacodynamic (PD) model components, or build higher fidelity models. See Model for more information.
Fit data — Fit nonlinear, mixed-effects models to data, and estimate the fixed and random effects, or fit the data using nonlinear least squares. For more information, see Analyze Data Using Models.
Generate diagnostic plots — For more information, see Analyze Data Using Models.
The software lets you work with different model structures, thus letting you try multiple models to see which one produces the best results.
Provides a command-line interface and an integrated software environment. For instructions, see the MATLAB installation documentation for your platform.
If you have installed MATLAB and want to check which other MathWorks® products are installed, enter
Statistics and Machine Learning Toolbox™ (Version 7.3 (R2010a) or greater)
Provides fitting tools including functions used to analyze nonlinear mixed effects.
|C Compiler||Required to prepare the model for accelerating simulations. For list of supported compilers, see Supported and Compatible Compilers.|
Toolbox extends the MATLAB technical computing environment with tools and widely used
algorithms for standard and large-scale optimization. These algorithms solve
constrained and unconstrained, continuous and discrete problems. If the
Toolbox product is installed, you can specify additional methods for
likelihood maximization. If you do not have this product, SimBiology uses
You can import tabular data into the SimBiology desktop or the MATLAB Workspace. The supported file types are
.txt. You can specify that the data is
in a NONMEM® formatted file. The import process interprets the columns according to the
From the SimBiology desktop, you can filter the raw data to suppress outliers, visualize data
using common plots (such as
stairs), and perform basic statistical
analysis. You also can use functions to process and visualize the data at the command
SimBiology provides an extensible modeling environment. You can do any of the following:
Create a PK model using a model construction wizard to specify the number of compartments, the route of administration, and the type of elimination.
Extend any model with pharmacodynamic (PD) model components, or build higher fidelity models.
Build or load your own SimBiology, or SBML model.
For more information on building SimBiology models, see What is a Model?.
Perform both individual and population fits to grouped longitudinal data:
Individual fit — Fit data using nonlinear least-squares method, specify parameter transformations, estimate parameters, and calculate residuals and the estimated coefficient covariance matrix.
Population fit — Fit data, specify parameter transformations, and estimate the fixed effects and the random sources of variation on parameters using nonlinear mixed-effects models.
You can use the following methods to estimate the fixed effects:
LME — Linear mixed-effects approximation
RELME — Restricted LME approximation
FO — First-order estimate
FOCE — First-order conditional estimate
For more information about each of these methods, see
Population fit using a stochastic algorithm — Fit data, specify parameter transformations, and estimate the fixed effects and the random sources of variation on parameters, using the Stochastic Approximation Expectation-Maximization (SAEM) algorithm. SAEM is more robust with respect to starting values. This functionality relaxes assumption of constant error variance.
For more information, see
In addition, you can generate diagnostic plots that show:
The predicted time courses and observations for an individual or the population
Observed versus predicted values
Residuals versus time, group, or predictions
Distribution of the residuals
A box-plot for random effects or parameter estimates from individual fitting
SimBiology extends MATLAB and lets you access pharmacokinetic modeling functionality at the command line and in the graphical SimBiology desktop.
Use the command line to write and save scripts for batch processing and to automate your workflow.
Use the SimBiology desktop to interactively change and iterate through the model workflow. The SimBiology desktop lets you encapsulate models, data, tasks, task settings, and diagnostic plots into one convenient package, namely a SimBiology project.
Furthermore, if you are using the SimBiology desktop and want to learn about using the command line, the MATLAB code capture feature in the desktop lets you see the commands and export files for further scripting in the MATLAB editor.
For an example showing pharmacokinetic modeling functionality at the command line, see Modeling the Population Pharmacokinetics of Phenobarbital in Neonates.
Acknowledgements for data in the
tobramycin.txt file are located in
/matlab/toolbox/simbio/simbiodemos folder. Data set is provided by
Dr. Leon Aarons (
The data in the
tobramycin.txt file were downloaded from the Web site
of the Resource Facility for Population Kinetics
http://depts.washington.edu/rfpk/service/datasets/index.html (no longer
active). Funding source: NIH/NIBIB grant P41-EB01975.
The original data set was modified as follows:
Header comments were removed.
The file was converted to a tab-delimited format.
Missing values in the
HT column were denoted with
." instead of
 Original Publication: Aarons L, Vozeh S, Wenk M, Weiss P, and Follath F. “Population pharmacokinetics of tobramycin.” Br J Clin Pharmacol. 1989 Sep;28(3):305–14.