Tablet containing a coated core
A tablet formulation which comprises a core containing a pharmaceutically active material, coated with a release retarding coating, surrounded by a casing layer which includes a second pharmaceutically active material.
1. A tablet formulation for oral administration comprising amoxycillin and clavulanate in a ratio of 30:1 to 1:1 in which a portion of the amoxycillin and all of the clavulanate is in a central core which is surrounded by a release-retarding coating layer and the remainder of the amoxicillin is in a casing layer surrounding the core, such that there is an initial quick release of amoxycillin from the casing layer and a sustained release of amoxycillin and clavulanate from the core.
2. A tablet formulation according to claim 1 wherein the core and the casing layer both comprise a compacted mixture of components.
3. A tablet formulation according to claim 1 wherein the release retarding coating is an enteric polymer.
4. A tablet formulation according to claim 1 further comprising one or more sub-coats beneath the release retarding coating layer.
5. A tablet formulation according to claim 1 further comprising one or more over-coats above the release retarding coating layer.
6. A tablet formulation according to claim 1 for oral administration twice a day.
7. A method of treating a bacterial infection in a patient in need thereof, which method comprises administering to said patient an effective amount of a formulation according to claim 1 .
8. A tablet according to claim 3 wherein the enteric polymer is cellulose acetate phthalate, cellulose acetate succinate, methylcellulose phthalate, ethylhydroxycellulose phthalate, polyvinylacetatephthalate, polyvinylbutyrate acetate, vinyl acetate-maleic anhydride copolymer, styrene-maleic mono-ester copolymer, methyl acrylate-methacrylic acid copolymer, or methacrylate-methacrylic acid-octyl acrylate copolymer, or a mixture thereof.
9. A tablet according to claim 8 wherein the enteric polymer coating is a methacrylic acid-methacrylate copolymer.
10. A tablet according to claim 3 wherein the enteric polymer further comprises a plasticiser.
11. A tablet according to claim 3 wherein the enteric polymer further comprises an anti-foaming agent.
12. A tablet according to claim 3 wherein the enteric polymer further comprises an anti-tack agent.
13. A tablet according to claim 1 wherein the amoxycillin is amoxycillin trihydrate.
14. A tablet according to claim 4 wherein the clavulanate is potassium clavulanate.
15. A tablet according to claim 4 wherein the sub-coat is hydroxypropylmethylcellullose.
16. A tablet according to claim 5 wherein the over-coat is hydroxypropylmethylcellullose, or a co-polymer of methacrylic acid and methyl methacrylate.
17. A tablet according to claim 1 wherein the casing layer is coated with a top coat.
18. A tablet according to claim 17 wherein the top coat is hydroxypropylmethylcellulose.
19. A tablet formulation according to claim 1 wherein the total weight of amoxycillin is from 25 to 75% in the central core.
20. A tablet formulation according to claim 1 wherein the total weight of amoxycillin is from 50 to 75% in the central core.
21. A tablet formulation according to claim 1 wherein the total weight of amoxycillin is from 75 to 25% in the casing layer.
22. A tablet formulation according to claim 1 wherein the total weight of amoxycillin is from 50 to 25% in the casing layer.
23. A tablet formulation for oral administration comprising amoxycillin and clavulanate in a ratio of 30:1 to 1:1 in which a portion of the amoxycillin and all of the clavulanate is in a central core which is surrounded by a release-retarding coating layer and the remainder of the amoxicillin is in a casing layer surrounding the core, such that there is an initial quick release of amoxycillin from the casing layer and a delayed release of amoxycillin and clavulanate from the core.
24. A tablet formulation according to claim 23 wherein the total weight of amoxycillin is from 25 to 75% in the central core.
25. A tablet formulation according to claim 23 wherein the total weight of amoxycillin is from 50 to 75% in the central core.
26. A tablet formulation according to claim 23 wherein the total weight of amoxycillin is from 75 to 25% in the casing layer.
27. A tablet formulation according to claim 23 wherein the total weight of amoxycillin is from 50 to 25% in the casing layer.
28. A tablet formulation according to claim 23 wherein the release retarding coating is an enteric polymer.
29. A tablet formulation according to claim 28 further comprising one or more sub-coats beneath the release retarding coating layer.
30. A tablet according to claim 29 wherein the sub-coat is hydroxypropylmethylcellullose.
31. A tablet formulation according to claim 23 further comprising one or wore over-coats above the release retarding coating layer.
32. A tablet according to claim 31 wherein the over-coat is hydroxypropylmethylcellullose, or a co-polymer of methacrylic acid and methyl methacrylate.
33. A tablet according to claim 23 wherein the casing layer is coated with a top coat.
34. A tablet according to claim 33 wherein the top coat is hydroxypropylmethylcellulose.
35. A tablet according to claim 34 wherein the enteric polymer is cellulose acetate phthalate, cellulose acetate succinate, methylcellulose phthalate, ethylhydroxycellulose phthalate, polyvinylacetatephthalate, polyvinylbutyrate acetate, vinyl acetate-maleic anhydride copolymer, styrene-maleic mono-ester copolymer, methyl acrylate-methacrylic acid copolymer, or methacrylate-methacrylic acid-octyl acrylate copolymer, or a mixture thereof.
36. A tablet according to claim 35 wherein the enteric polymer is a methacrylic acid-methacrylate copolymer.
37. A tablet according to claim 28 wherein the enteric polymer further comprises a plasticiser.
38. A tablet according to claim 28 wherein the enteric polymer further comprises an anti-foaming agent.
39. A tablet according to claim 28 wherein the enteric polymer further comprises an anti-tack agent.
40. A tablet according to claim 23 wherein the amoxycillin is amoxycillin trihydrate.
41. A tablet according to claim 23 wherein the clavulanate is potassium clavulanate.
42. A tablet formulation according to claim 23 for oral administration twice daily.
43. A method of treating a bacterial infection in a patient in need thereof, which method comprises administering to said patient an effective amount of a formulation according to claim 23 .