Misuse preventative, controlled release formulation

A solid, compressed controlled release formulation, comprising:

• (a) a 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 controlled release coat surrounding the core;
• and
• (c) a plurality of controlled release microparticles having a pharmaceutically active agent disposed therein, wherein the microparticles are disposed within the core, the coat, or both the core and the coat, 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.