In the last few decades, a number of probabilistic models
for drug delivery have been developed. Of particular
interest are those that model controlled release systems
to provide targeted dose delivery. Controlled release
is achieved by using polymers with dierent dissolution
characteristics. We present here a model based
on Monte Carlo and Cellular Automata approaches, for
simulating drug release from coated microspheres in the
gastro-intestinal tract. Controlled release is obtained using ethylcellulose as the coating polymer. Modelling features, such as the drug and coating dissolution are nontrivial, since material is non-homogenously dispersed
and the dissolution exhibits complex behaviour. Important
underlying mechanisms of the process, such as
erosion, are described here