Double-release three-layered brivaracetam tablet and preparation method thereof

A double-release three-layered brivaracetam tablet, of comprising an immediate-release layer, a retarding layer, and a sustained-release layer, wherein the immediate-release layer, the retarding layer, and the sustained-release laver are superposed;

• wherein
• the retarding layer contains no drug and is located in a middle;
• at least 60% of a surface area of each of the immediate-release layer and the sustained-release layer that is in contact with the retarding layer is covered by the retarding layer;
• and
• a sustained-release material in the retarding layer contains a waxy sustained-release material;
• a drug substance is selected from one or more of brivaracetam, a pharmaceutically acceptable complex thereof, a pharmaceutically acceptable salt thereof, a pharmaceutically acceptable solvate thereof, a pharmaceutically acceptable hydrate thereof, and other related structural derivatives of levetiracetam;
• the double-release three-layered brivaracetam tablet has the following characteristics:
• when tested using a paddle method at 50 rpm, in medium of pH 1.2, pH 4.5, pH 6.8, or water in an aqueous medium, a dissolution rate of the drug substance is greater than or equal to 25% at 0.5 hour, from 30% to 65% at 2 hours, greater than or equal to 65% at 6 hours, and greater than or equal to 80% but less than 100% at 14 hours;
• and after 0.5 hour, the double-release three-layered brivaracetam tablet is released in vitro in a zero-order release manner.