Pharmaceutical companies today face a growing demand for more complex drug designs. In the past few decades, a number of probabilistic models have been developed, for the purpose of giving a better insight into the microscopic features of these complex designs. Of particular interest are those models that simulate controlled release systems to provide targeted dose delivery. Controlled release is achieved by using polymers with different dissolution characteristics. We present here a model of a drug delivery system based on Monte Carlo methods, as a framework for Cellular Automata mobility, and show a solution for model enhancement through parallelisation. The objective is the high performance simulation of targeted drug release in the gastrointestinal tract, from a capsule composed of ethylcellulose coated microspheres. The overall aim is to understand the importance of various molecular effects with respect to system evolution over time. Important underlying mechanisms of the process, such as erosion and diffusion, are described.