SimBiology 

SimBiology lets you represent a model of a biological or a pharmacological mechanism just as you would draw it on a piece of paper. It includes a block diagram editor that lets you graphically build models by dragging and connecting blocks. You can also programmatically build and manage models using MATLAB functions.
In addition to the environment for building models, SimBiology includes a library of standard PK models. Or, you can import models from a Systems Biology Markup Language (SBML) file.
Building a Model in SimBiology
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Build and simulate a model using the SimBiology desktop.
SimBiology provides three basic blocks to build your models:
SimBiology uses a reactionnetwork modeling approach that lets you model a variety of dynamic biological systems such as signaling pathways, metabolic networks, and the pharmacokinetics/pharmacodynamics of drugs. Each reaction in the model defines the structure and the rate of the individual interaction. SimBiology uses massbalance principles to automatically translate this network representation of the model into a set of ordinary differential equations (ODEs) that mathematically describe the dynamics of your system.
The equation view displays the underlying ODEs defining the model.
SimBiology provides two additional modeling constructs for specifying model dynamics:
Taken together, model expressions—that is, reactions, rules, and events—fully describe the mathematics of the model.
Model variants let you store a set of parameter values or initial conditions that are different from the base model configuration. Using variants, you can easily simulate alternate scenarios and whatif hypotheses without creating multiple copies of the model. For example, you can use model variants to specify parameter values for different cell lines, drug candidates, or animal species.
SimBiology allows you to define and evaluate bolus and infusion dosing strategies. You can link the dose to the appropriate species in the model to stipulate the administration route (intravenous, subcutaneous, oral, or topical). You can test hybrid dosing strategies by including multiple dosing schedules during model evaluation. Similarly, you can assess the benefit of combination therapies and determine the optimal dosing strategy by combining dosing schedules targeting different model species.