Any pharmaceutical preparation for oral administration with controlled release of active ingredient in the small bowel, on the basis of active ingredient carriers provided with at least one active ingredient which are provided with an inner layer to control the release of active ingredient and with a gastro-resistant coating layer disposed thereon, which is characterized in that the inner layer is formed from at least two diffusion layers whose permeability for the diffusing active ingredient decreases from the inside to the outside, and a method for the production thereof, are described.
