MATLAB: Add multiple doses in ODEsolver

Question

I am trying to simulate multiple doses in a two compartment model. i have these odes for change in amount in each compartment.

d_amt_dt(1)= -(k12.*amt(1)) -(k10.*amt(1))+ (k21.*amt(2));

d_amt_dt(2) = (k12.*amt(1)) -(k21.*amt(2));

d_amt_dt = d_amt_dt';

For a single dose, I just change the initial condition amt1_0 = amount of dose given and get the expected output. However, how do I simulate multiple doses, e.g. every hour?

I can do this in Simbiology but I was wondering if there is a way to write code for that?

Answer 1

Because doses introduce discontinuities in the solution, you basically need to stop the ODE simulation every time a dose is applied, update the appropriate states for the dose, and call the ODE solver with the updated initial conditions. This is what SimBiology does behind the scenes for you.