The present invention relates to a granule including a solid core on which an active principle supported, said active principle being selected from among gamma-hydroxybutyric acid or one of the pharmaceutically acceptable salts thereof, said granule further including one or more compounds which are supported on said solid core and which are capable of releasing gas, and one or more diluents, said granule being characterized in that it is coated with a membrane and in that the solid core is 15 to 50 wt % with respect to the total weight of the granule.
