Porous coating for the controlled release of drugs, said coating comprising a porous structure with pores adapted to act as reservoirs or as passages for a drug, in such a way that said drug can move from the external environment to/from or through said pores, characterized by the fact that at least a group of said pores are partially or totally containing an element introduced during or after the loading of the drug in the reservoir pores, in such a way that said drug can still move towards the external environment but in a more restricted manner.