Controlled release of drugs is showing an increasing number of advantages, including lower side effects and a better patient compliance, becoming one of the more dynamic fields on pharmaceutical research. Ultrasound-assisted compression can provide a new tool to prepare Controlled Release Systems in a simple way. We have applied the Percolation Theory, a new theory derived from Statistical Physics to the study of controlled release inert matrix tablets, obtained with the assistance of ultrasound. The continuum percolation model provides a physical basis for a rational design of systems containing one thermoplastic component, compacted with the assistance of ultrasonic energy. This model can explain the important decrease in the excipient percolation threshold, a critical point that governs the mechanical and release properties of the matrix. An important decrease in the preparation cost, a weight reduction (especially interesting for high drug doses) and a lower variability on the release kinetics, can be obtained applying this technology to the preparation of Controlled Release Systems. Nevertheless, possible consequences of the increase in temperature must be taken into account for thermolabile drugs.