Osmotic pump controlled release tablet and preparation method thereof

An oral osmotic pump controlled release tablet comprising ethyl cellulose and povidone as film forming materials of a semipermeable membrane, the osmotic pump controlled release tablet including a tablet core, a semipermeable membrane and an optional film coating layer, wherein the weight ratio of ethyl cellulose and povidone is 1:1 to 4:1;

• and wherein the tablet core comprises a drug-containing layer and a push layer, wherein:
• (1) an angle θ1 formed by an outer curved surface of the drug-containing layer and a lateral surface of the drug-containing layer is 130°-180°, and an angle θ2 formed by an outer curved surface of the push layer and a lateral surface is 95°-120°, and
• (2) a ratio of L1/r is 0.36-1.0, wherein L1 is a vertical distance from a central vertex of the outer curved surface of the drug containing layer to a plane formed by an intersection line between the outer curved surface of the drug containing layer and the lateral surface, and r is a radius of the tablet core, and a ratio L2/r is 0.04-0.27, wherein L2 is a vertical distance from a central vertex of the outer curved surface of the push layer to a plane formed by an intersection line between the outer curved surface of the push layer and the lateral surface, and r is a radius of the tablet core.