Abstract: Controlled release pharmaceutical tablet having a lenticular form consisting of three layers of which the central one or core (a) contains the active principle and the two outer layers or barriers (b) and (c) comprise gellable and/or erodible polymeric material, said barrier layers being equal or different among themselves for composition and/or thickness, while the central layer has a limited external annular surface exposed to the dissolution medium, through which the active principle is released.

Abstract: A pharmaceutical tablet capable of releasing the active ingredients contained therein at subsequent times produced via the steps of: a) preparing a tablet consisting of three superposed layers, the upper layer containing an active ingredient, the intermediate layer not containing any active ingredient and forming a barrier-type layer, and the lower layer containing an active ingredient, said upper layer presenting a raised top, b) coating the tablet entirely with an impermeable polymeric film, and c) removing said raised top and thus allowing contact of the abraded upper layer surface with the environment.

Abstract: Pharmaceutical tablets releasing the active substance after a definite period of time, consisting of: a core containing the active substance and polymeric substances which swell and/or gel and/or erode on contact with water or with aqueous liquids; a layer applied externally to said core, suitable to prevent the immediate release of the active substance contained in the core and to allow the release of said active substance after a definite period of time, consisting of natural and/or synthetic polymeric materials of the class of the hydrophilic polymers which erode and/or gel and/or dissolve in an aqueous medium; a possible gastroresistant and enterosoluble coating.