Modified release formulations of a bupropion salt

1. A modified release osmotic dosage form comprising

a core comprising bupropion hydrobromide; and

a semipermeable membrane surrounding the core;

wherein the bupropion hydrobromide is present in a therapeutically effective amount, and wherein said dosage form releases the bupropion hydrobromide by dispensing the bupropion hydrobromide from the core via at least one passageway in the membrane by pressure created in the core by osmosis and/or by the expansion of a swellable material which forces the bupropion hydrobromide to be dispensed from core of the dosage form.

2. The modified release osmotic dosage form according to claim 1 , wherein said dosage form exhibits an in-vitro release rate such that after 2 hours 0 to 20% by weight of the bupropion hydrobromide is released, after 4 hours from 15% to 45% by weight of the bupropion hydrobromide is released, after 8 hours, from 40% to 90% by weight of the bupropion hydrobromide is released, and after 16 hours, more than 80% by weight of the bupropion hydrobromide is released.

3. The modified release osmotic dosage form according to claim 1 , wherein the core further comprises at least one osmagent.

4. The modified release osmotic dosage form according to claim 3 , wherein said at least one osmagent is selected from the group consisting of sodium chloride, calcium chloride, calcium lactate, sodium sulfate, lactose, glucose, sucrose, mannitol, urea, and mixtures thereof.

5. The modified release osmotic dosage form according to claim 3 , wherein said at least one osmagent is present in admixture with said bupropion hydrobromide.

6. The modified release osmotic dosage form of claim 1 , wherein the dosage form exhibits an in-vitro release rate such that after 2 hours no more than 40% is released, after 4 hours 40-75% is released, after 8 hours at least 75% is released and after 16 hours at least 85% is released.

7. The modified release osmotic dosage form according to claim 1 , wherein said core comprises bupropion hydrobromide arranged in a layered, contacting arrangement, with a swellable material to provide a core with two or more layers.

8. The modified release osmotic dosage form of claim 1 , wherein the semipermeable membrane comprises at least one polymer, at least one wax, or a combination thereof.

9. The modified release osmotic dosage form of claim 1 , further comprising a control-releasing coat.

10. The modified release osmotic dosage form of claim 9 , wherein the control releasing-coat comprises at least one water-insoluble water-permeable film-forming polymer, at least one water-soluble polymer, and, optionally, at least one plasticizer.