The invention provides an oral pharmaceutical tablet for controlled release of mesalazine or a pharmaceutically acceptable salt thereof as active ingredient with a core and a gastro-resistant outer coating, wherein the core comprises mesalazine and a hydrophilic matrix consisting of a mixture of hydroxypropylmethyl cellulose (HPMC) having a different viscosity and the gastro-resistant outer coating comprises a pH- dependent release polymer, with the pharmaceutically acceptable excipients. The invention also refers to the process for obtaining said oral pharmaceutical tablet and to said oral pharmaceutical tablet of controlled release of mesalazine for treating ulcerative colitis.
