Patent ID: 8920834

Claim:
A solid, compressed controlled release formulation, comprising: (a) a core comprising a first layer and a second layer, the core comprising a superabsorbent material comprising a cross-linked acrylic acid polymer characterized in that the cross-linked acrylic acid polymer absorbs at least 15 times its own weight of water, the superabsorbent material comprising from 30% to 70% (w/w) of the core; (b) a plurality of controlled release microparticles disposed within the core and having a pharmaceutically active agent disposed therein; and (c) a coat surrounding the core, the formulation having a hardness from about 200 N to about 400 N, and wherein the formulation (i) when intact and exposed to an aqueous medium, the pharmaceutically active agent is released from the formulation over a prolonged period of time, (ii) when crushed to break the controlled release coat and exposed to 2 mL of water, the superabsorbent material absorbs all of the water and creates a hard gel that traps the microparticles, whereupon the hard gel and the microparticles provide controlled release of the pharmaceutically active agent disposed within the microparticles, and (iii) when broken and exposed to 900 mL of water in a U.S.P. Type I Apparatus with stirring at 100 rpm for 30 minutes at 37° C., less than about 50% by weight of the pharmaceutically active agent originally present in the formulation before it was broken is released into the water.