The present invention relates to a solid oral dosage form, enabling the modified release of at least one active principle, containing at least microparticles containing said active agent and at least one viscosifying agent in a form that is isolated from said microparticles of the active agent, characterised in that said microparticles have an average diameter of 100 to 600 μm, and are made up of a core containing at least said active principle and coated with at least one coating layer, said core being made up of a supporting particle covered by a layer including at least said active agent, and said coating layer being made of a material made up of at least 25 to 70 wt % of at least one water-insoluble polymer A relative to the total weight of said coating layer, 30 to 75 wt % of at least one polymer B that is not soluble in water with a pH of less than 5 but is soluble in water with a pH of more than 7 relative to the total weight of said coating layer, and 0 to 25 wt % of at least one plasticiser relative to the total weight of said coating layer, said polymers A and B having a weighted ratio of polymer(s) B/polymer(s) A of 0.25 to 4, said coating layer accounting for at least 35 wt % relative to the total weight of said microparticle.
