Pharmaceutical pellets comprising tamsulosin

1. A pharmaceutical dosage form comprising a plurality of pellets, wherein each pellet comprises:

a. a pellet core having a diameter within the range of 0.3-0.9 mm and comprising a tamsulosin hydrochloride, microcrystalline cellulose, a pharmaceutically acceptable water permeable acrylic polymer and water; and

b. an outer layer coat surrounding said core which comprises a pharmaceutically acceptable acid-resistant acrylic polymer, wherein the mass of said outer layer coat, calculated on a dry pellet core basis, is within the range of 2.5-15%; and

wherein the plurality of pellets exhibits a dissolution release profile in simulated gastric fluid using Ph. Eur. basket method at 100 rpm which includes releasing less than 10% of the tamsulosin during the first two hours.

2. The dosage form according to claim 1 , wherein said pellet core contains 0.05-5.0% mass of tamsulosin hydrochloride, 50-95% mass of microcrystalline cellulose, 2.5-25% mass of the acrylic polymer, 2-10% mass of water, and 0-25% mass of other pharmaceutically acceptable excipients, calculated on a dry pellet core basis.

3. The dosage form according to claim 1 , wherein said pellet core contains 2.5-5% mass of water, calculated on a dry pellet core basis.

4. The dosage form according to any one of claim 1 , wherein said water permeable acrylic polymer is an Eudragit L polymer.

5. The dosage form according to claim 1 , wherein the composition of said outer layer coat comprises 25-75 mass % of said acid resistant acrylic polymer, calculated on a dry basis.

6. The dosage form according to claim 5 , wherein said acid-resistant acrylic polymer is an Eudragit L polymer.

7. The dosage form according to claim 6 , wherein the acrylic polymer contained in said pellet core is identical with said acid-resistant acrylic polymer in said outer layer coat.

8. The dosage form according to claim 1 , wherein said mass of said outer layer coat, calculated on a dry pellet core basis, is within the range of 8-12%.

9. The dosage form according to claim 1 , wherein said coated pharmaceutical pellet exhibits a dissolution release profile in a phosphate buffer of pH 6.8 using Ph. Eur. basket method at 100 rpm which includes releasing 15-45% of the tamsulosin in 30 minutes.

10. The dosage form according to claim 9 , wherein dissolution profile includes releasing 30-65% of the tamsulosin in one hour.

11. The dosage form according to claim 10 , wherein dissolution profile includes releasing more than 80% of the tamsulosin in five hours.

12. The dosage form according to claim 1 , wherein said dosage form is a capsule or sachet.

13. The dosage form according to claim 1 , wherein a total amount of tamsulosin hydrochloride contained therein is within the range of 0.1 to 1 mg.

14. The dosage form according to claim 13 , wherein said total amount of tamsulosin hydrochloride is 0.2, 0.4, or 0.8 mg.

15. A process, which comprises:

a. granulating a mixture of tamsulosin hydrochloride, microcrystalline cellulose, acrylic polymer, water and optionally auxiliary ingredients to form wet pellet cores,

b. drying said wet pellet cores to a residual amount of water of 2-10%;

c. sieving said dried pellet cores to obtain a fraction within the size range of 0.3-0.9 mm;

d. coating said sieved dried pellet cores with a coating composition that comprises an acid-resistant water soluble acrylic polymer; and

e. drying said coated pellet;

wherein said coating step (d) is sufficient to provide said dried coated pellet with 2.5-15 mass % of said coating composition, calculated on the dry pellet core basis.

16. The process of claim 15 , wherein said coating step (d) is performed in a high shear mixer/granulator.

17. The process of claim 15 , wherein said coating is performed in a fluid bed coater.

18. The process of claim 15 , wherein said coating is performed on a coating pan.

19. A process, which comprises:

(a) granulating a mixture of tamsulosin hydrochloride, microcrystalline cellulose, acrylic polymer, water and optionally auxiliary ingredients to form wet pellet cores,

(b) drying said wet pellet cores to a residual amount of water of 2-10%; sieving said dried pellet cores to obtain a fraction within the size range of 0.3-0.9 mm;

(c) coating said sieved dried pellet cores with a coating composition that comprises an acid-resistant water soluble acrylic polymer;

(d) drying said coated pellet;

(e) testing a sample of said dried coated pellets for dissolution rate in a simulated gastric fluid; and

(f) repeating the coating process on the remaining dried coated pellets until a desired amount of release is achieved in said testing step (e).

20. A method for treating the symptoms of benign prostatic hyperplasia, which comprises administering an effective amount of the pellets according to claim 1 , to a patient in need thereof.

21. The dosage form according to claim 5 , wherein said outer layer coat comprises 30 to 75% of said acid-resistant acrylic polymer.