Patent ID: 8568782

Claim:
A gastroresistant rifaximin microgranule comprising rifaximin directly coated with a gastroresistant polymeric material formulation, wherein said gastroresistant polymeric material formulation comprises a gastroresistant polymer which is insoluble at pH values from about 1.5 to about 4 and is soluble at pH values from about 5.0 to about 7.5, wherein the gastroresistant rifaximin microgranule has a diameter of from about 1 micron to about 900 microns, wherein said rifaximin is released at a pH higher than 5.0, and wherein the gastroresistant polymer is selected from the group consisting of acrylic polymer, methacrylic acid copolymers, methacrylic acid copolymers with an acrylic or methacrylic ester, cellulose acetate phthalate, hydroxypropyl cellulose acetate phthalate, hydroxypropyl methylcellulose phthalate, polyvinyl acetate phthalate, methacrylic acid ethylacrylate copolymer, and mixtures thereof.