Patent ID: 8637080

Claim:
A rupturing controlled release device comprising: a) a core comprising at least one active agent and at least one excipient; b) a semipermeable membrane enclosing the core and comprising a first cellulose acetate, a second cellulose acetate, a plasticizer, at least one preformed passageway there through, wherein the first cellulose acetate comprises 7-10% by weight of hydroxyl groups and 30-36% by weight of acetyl groups, and the second cellulose acetate comprises 3-5% by weight of hydroxyl groups and 37-43% by weight of acetyl groups, and a weakened region; and c) a rupture-controlling subcoat between the core and the semipermeable membrane and consisting essentially of hydroxypropyl methylcellulose and poly(ethylene glycol), wherein the semipermeable membrane ruptures at the weakened region during use due to the increase of the internal pressure of the device; the rupture-controlling subcoat reduces the size of a rupture initially formed in the semipermeable membrane during use as compared to an otherwise similar osmotic device comprising no rupture-controlling subcoat; the osmotic device continues to provide a controlled release of active agent from the core after rupture of the semipermeable membrane for a period of eight hours up to 12 hours, 16 hours, 18 hours, 20 hours, a day, or more than a day; and the invention does not include embodiments wherein the membrane breaks catastrophically thereby releasing the contents of the core in a burst or rapid manner.