Add to ORKGHydrogels are materials largely used in the formulation of pharmaceuticals since, in principle, they could produce a release system of zero-order kinetics, which is of great therapeutic interest. In this paper, a model was proposed for the description of the main transport phenomena involved in the drug release process from hydrogel matrices (water diffusion, polymer swelling, drug diffusion and polymer dissolution); the model predictions are successfully compared with a large set of experimental data, obtained working with matrices systems based on HPMC (Hydroxy Propyl Methyl Cellulose). The proposed model was found able to reproduce main features of the observed phenomena, it can thus be adopted for prediction of the performances of drug ...