A PHARMACEUTICAL TABLET SYSTEM THAT FLOATS ON GASTRIC FLUID FOR MULTIPULSE RELEASE OF ACTIVE SUBSTANCE, AND RESPECTIVE PROCESSES OF PRODUCING SAME AND A CUP-SHAPED ENVELOPE OF SAME

摘要

A tablet system for prolonged floating in or on gastric fluid for releasing therein pharmaceutically active substances in an alternate succession of substance release and no-release periods is made up of a multilayered core placed in a cup-shaped envelope. The core is made up of release layers and no-release layers devoid of pharmaceutically active substance, superposed in alternate succession. The cup-shaped envelope covers bottom and side surfaces of the core while leaving exposed an upper surface of the core. The cup-shaped envelope provides for buoyancy by being formed of a compression-sintered mixture comprising hydrophobic material and inert powdered filler. The hydrophobic material is composed of fatty and/or waxy material capable of being sintered by compression and whose bulk density is lower than gastric fluid density. The powdered filler has a loose powder density that is lower than gastric fluid density.