 The aim of the present investigation was to understand the swelling behavior of HPMC and PEO-based matrices and to evaluate the impact of porosity on the swelling kinetics. It was noticed that the HPMC has higher swelling rates but both undergo diffusion-oriented swelling mechanism. It could also be concluded that the porosity has a marked influence in the development of gel layer on the surface of these matrices. This article was authored by Mohammed Essasim, Mohammed U Gori and Barbara Aconley.