Q: How can I solve a compartmental model where the rate constants are time-varying?

A: In SAAM II, it is possible to define time-varying rate constants by simply entering, either in the Loss or Transfer Attributes Window or in the Equations Window, the equation defining the rate constant. For example, a Michaelis-Menten type of reaction can be defined by using this single-compartment model:

where the rate constant k(0,1) is defined as:

k(0,1) = Km / (Vmax + q1)

thus defining a nonlinear reaction. k(0,1)will disappear as a parameter, and Km and Vmax will appear instead in the parameter window.

The same holds for a generic parameter in the model: any parameter could in fact be defined as time-varying.

For more information about the capabilities of SAAM II for entering user-defined generic, multiple-order, linear or nonlinear differential equations, see also the links:

1. How can I solve a differential equation that cannot be written in compartmental form?
2. How can I solve a second-order differential equation?

<< Back to Support Page