The present invention relates to a formulation containing Mesalazine in a stable form, obtained by coating the starting core with a first membrane in non-aqueous solution said core containing Mesalazine at a high concentration, greater than 90%, obtained by producing starting cores with Active Substance content greater than 97%. The formulation according to the present invention containing Mesalazine with specific release in the colon in particular the capsule formulation containing 500 mg of Mesalazine with specific release in the colon.
