Formulation and process for drug loaded cores

1. A controlled release pellet consisting essentially of:

a) an inert core that is water swellable;

b) a drug layer applied to the inert core comprising:

i) metoprolol succinate;

ii) a binder; and

iii) optionally a surfactant;

c) a controlled release coating surrounding the drug layer comprising:

i) 75-90% of a water insoluble film forming polymer selected from the group consisting of cellulose acetate, cellulose acetate butyrate, ethyl cellulose, hydroxypropyl cellulose acetate, hydroxypropyl methyl phthalate and cellulose acetate phthalate or mixtures thereof.

2. A controlled release pellet as defined in claim 1 , wherein the inert core has a diameter that is less than 30 mesh.

3. A controlled release pellet as defined in claim 1 , wherein the inert core has a diameter that is less than 40 mesh.

4. A controlled release pellet as defined in claim 1 , wherein the inert core has a diameter of about 30 to 200 mesh.

5. A controlled release pellet as defined in claim 1 , wherein the inert core has a diameter of about 40 to 120 mesh.

6. A controlled release pellet as defined in claim 1 , wherein the inert core has a diameter of about 60 to 80 mesh.

7. The controlled release pellet as defined in claim 1 , wherein the binder is selected from the group consisting of polyvinyl pyrrolidone, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methylcellulose, polyacrylate, ethylcellulose, or mixtures of the thereof.

8. The controlled release pellet as defined in claim 7 , wherein the binder is hydroxypropyl methylcellulose.

9. The controlled release pellet as defined in claim 1 , wherein the drug layer further comprises a surfactant.

10. The controlled release pellet as defined in claim 9 , wherein the surfactant is selected from the group consisting of fatty acids, chelating agents, bile salts or mixtures thereof; capric acid, oleic acid and their monoglycerides, alkyl sulfates, sodium lauryl sulfate, sodium dodecyl sulfate, polysorbate 80, citric acid and phytic acid.

11. The controlled release pellet as defined in claim 10 , wherein the surfactant is polysorbate 80.

12. The controlled release pellet as defined in claim 1 , wherein the water insoluble film-forming polymer is cellulose acetate butyrate.

13. The controlled release pellet as defined in claim 1 , wherein the emulsifier is selected from the group consisting of phospholipids, propylene glycol, polysorbates, poloxamer, glyceryl monostearate, other pharmaceutical emulsifiers or mixtures thereof.

14. The controlled release pellet as defined in claim 1 , wherein the emulsifier is a poloxamer.

15. The controlled release pellet as defined in claim 1 , wherein the controlled release coating further comprises a plasticizer.

16. The controlled release pellet as defined in claim 15 , wherein the plasticizer is selected from the group consisting of polyethylene glycol, propylene glycol, glycerol, triacetin, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dibutyl sebacate, triethyl citrate, tributyl citrate, triethyl acetyl citrate, castor oil, poloxamer and varying percentages of acetylated monoglycerides.

17. The controlled release pellet defined in claim 1 that exhibits the following dissolution profile when tested in a USP Type 2 apparatus at 75 rpm and 37° C. in a phosphate buffer with a pH of 7.5,

0-25% of the metoprolol is released after 2 hours;

10-45% of the metoprolol is released after 4 hours;

35-75% of the metoprolol is released after 8 hours;

not less than 75% of the metoprolol is released after 16 hours.

18. An oral pharmaceutical tablet that comprises the controlled release pellet as defined in claim 1 .

19. An oral pharmaceutical capsule that comprises the controlled release pellet as defined in claim 1 .

20. The oral pharmaceutical tablet that is defined in claim 18 that further comprises an immediate release form of metoprolol.

21. The oral pharmaceutical capsule that is defined in claim 19 that further comprises an immediate release form of metoprolol.

22. The oral pharmaceutical tablet as defined in claim 20 that exhibits the following dissolution profile when tested in a USP Type 2 apparatus at 75 rpm and 37° C. in a phosphate buffer with a pH of 7.5,

0-50% of the metoprolol is released after 2 hours;

10-60% of the metoprolol is released after 4 hours;

25-80% of the metoprolol is released after 8 hours;

not less than 50% of the metoprolol is released after 16 hours.

23. The oral pharmaceutical tablet as defined in claim 22 that exhibits the following dissolution profile when tested in a USP Type 2 apparatus at 75 rpm and 37° C. in a phosphate buffer with a pH of 7.5,

10-40% of the metoprolol is released after 2 hours;

20-50% of the metoprolol is released after 4 hours;

35-75% of the metoprolol is released after 8 hours;

not less than 60% of the metoprolol is released after 16 hours.

24. The oral pharmaceutical capsule as defined in claim 21 that exhibits the following dissolution profile when tested in a USP Type 2 apparatus at 75 rpm and 37° C. in a phosphate buffer with a pH of 7.5,

0-50% of the metoprolol is released after 2 hours;

10-60% of the metoprolol is released after 4 hours;

25-80% of the metoprolol is released after 8 hours;

not less than 50% of the metoprolol is released after 16 hours.

25. The oral pharmaceutical capsule as defined in claim 24 that exhibits the following dissolution profile when tested in a USP Type 2 apparatus at 75 rpm and 37° C. in a phosphate buffer with a pH of 7.5,

10-40% of the metoprolol is released after 2 hours;

20-50% of the metoprolol is released after 4 hours;

35-75% of the metoprolol is released after 8 hours;

not less than 60% of the metoprolol is released after 16 hours.

26. The pharmaceutical tablet as defined in claim 20 that exhibits a peak plasma level between 3 and 8 hours after administration.

27. The pharmaceutical tablet as defined in claim 26 that exhibits a peak plasma level between about 4.5 hours to about 7.5 hours after administration.

28. The pharmaceutical capsule as defined in claim 21 that exhibits a peak plasma level between 3 and 8 hours after administration.

29. The pharmaceutical capsule as defined in claim 28 that exhibits a peak plasma level between about 4.5 hours to about 7.5 hours after administration.

30. The pharmaceutical tablet as defined in claim 20 that exhibits a C max of less than 300 ng/ml.

31. The pharmaceutical tablet as defined in claim 30 that exhibits a C max of less than 275 ng/ml.

32. The pharmaceutical tablet as defined in claim 31 that exhibits a C max of between 200 ng/ml and 275 ng/ml.

33. The pharmaceutical capsule as defined in claim 21 that exhibits a C max of less than 300 ng/ml.

34. The pharmaceutical capsule as defined in claim 33 that exhibits a C max of less than 275 ng/ml.

35. The pharmaceutical capsule as defined in claim 34 that exhibits a C max of between 200 ng/ml and 275 ng/ml.

36. A controlled release pellet as defined in claim 1 , wherein the inert core is microcrystalline cellulose.

37. A process for preparing a controlled release pellet consisting essentially of:

a) dissolving or suspending metoprolol succinate in an aqueous medium;

b) applying the aqueous medium with the dissolved or suspended metoprolol succinate onto a water swellable inert core to create a drug layer on the inert core; and

c) applying a controlled release coating to the drug layer, wherein the controlled release coating layer comprises:

i) 75-90% of a water insoluble film forming polymer selected from the group consisting of cellulose acetate, cellulose acetate butyrate, ethyl cellulose, hydroxypropyl cellulose acetate, hydroxypropyl methyl phthalate and cellulose acetate phthalate or mixtures thereof;

ii) 2-10% of a channeling agent comprising methacrylic acid copolymer; and

iii) 5-15% of an emulsifier;

and wherein said pellet exhibits the following dissolution profile when tested in a USP Type 2 apparatus at 75 rpm and 37° C. in a phosphate buffer with a pH of 7.5;

0-40% of the metoprolol succinate is released after 2 hours;

5-50% of the metoprolol succinate is released after 4 hours;

25-80% of the metoprolol succinate is released after 8 hours;

not less than 50% of the metoprolol succinate is released after 16 hours.