Milled particles

• US 6,634,576 B2
• Filed: 08/29/2001
• Issued: 10/21/2003
• Est. Priority Date: 08/31/2000
• Status: Expired due to Term

• Current Assignee: Jagotec Ag (Vectura Group Ltd.)
• Original Assignee: RTP Pharma Corporation.
• Inventors: Verhoff, Frank, Millar, Fay, Pace, Gary W., Snow, Robert A.
• Primary Examiner(s): Rosenbaum, Mark
• Application Number:
  US09/940,864
• Publication Number:
  US 20020047058A1
• Time in Patent Office: 783 Days
• Field of Search: 241/21, 241/184, 241/171, 241/172, 241/23, 241/24.12
• US Class Current: 241/21
• CPC Class Codes: A61K 9/14 Particulate form, e.g. powders, Processes for size reducing of pure drugs or the resulting products, Pure drug nanoparticles microspheres A61K9/16; microcapsules A61K9/50; nanocapsules, nanoparticles of the matrix type A61K9/51

Abstract

A process for milling a solid substrate in the milling chamber of a dispersion or media mill in the presence of a two or more compositions of milling media bodies is disclosed wherein all milling media bodies contribute to the grinding of the solid substrate and wherein at least one composition of media bodies provides fragments of milling media bodies that are retained with the milled solid substrate particles in the form of a synergetic commixture produced in the milling process. More specifically, a process is disclosed for preparing a synergetic commixture comprising small particles of a solid substrate and small particulates of a first material of a desired size comprising the steps of (a) providing to the milling chamber of a media mill a contents comprising a pre-mix of a solid substrate, a fluid carrier, a plurality of milling bodies of a first material having a fracture toughness K_c1, and a plurality of milling bodies of a second material having a fracture toughness K_c2; (b) operating the media mill to grind the solid substrate and degrade at least a portion of the milling bodies of first material to produce a dispersion in the fluid carrier comprising a synergetic commixture of small particulates of the first material and small particles of the solid substrate having a desired size equal to or less than a size Sp; (c) separating the dispersion from any milling bodies and solid substrate particles having a size larger than S_p; and (d) optionally removing the fluid carrier from the dispersion to form a synergetic commixture free of fluid and comprising the particles and the small particulates, wherein K_C2 is greater than K_C1.

Claims

1. A process for preparing a synergetic commixture comprising small particles of a solid substrate and small particulates of a first material of a desired size, said process comprising:

a) providing to a milling chamber of a media mill a contents comprising a pre-mix of a solid substrate, a fluid carrier, a plurality of milling bodies of a first material, and a plurality of milling bodies of a second material;

b) operating said media mill to grind said solid substrate and degrade at least a portion of said milling bodies of the first material to produce a dispersion in said fluid carrier comprising a synergetic commixture of small particulates of said first material and small particles of said solid substrate having a desired size equal to or less than a size S_p;

c) separating said dispersion from any residual milling body, piece of milling body, and solid substrate having a size larger than S_p; and

d) optionally removing said fluid carrier from said dispersion to form a dry synergetic commixture comprising said particles and said small particulates;

wherein the milling bodies of said first material are fractured and eroded by the milling bodies of said second material, the milling bodies of said second material are essentially resistant to fracture and erosion in the milling process, and S_p is smaller than the size of the milling bodies of the second material.

2. The process of claim 1, wherein the premix comprises one or more than one surface active substance.

3. The process of claim 1, further comprising the addition of one or more than one surface active substance.

4. The process of claim 3, wherein the one or more than one surface active substance is selected from the group consisting of phospholipids, natural surfactants, nonionic surfactants, anionic surfactants, cationic surfactants, and colloidal clays.

5. The process of claim 3, wherein the one or more than one surface active substance is a phospholipid.

6. The process of claim 5, wherein the phospholipid is selected from the group consisting of egg lecithin, egg phosphatidylcholine, soy phosphatidylcholine, dimyristoyl phosphatidylglycerol, hydrogenated egg phosphatidylcholine, hydrogenated soybean phosphatidylcholine, and combinations thereof.

7. The process of claim 1, wherein the solid substrate is selected from the group consisting of a solid pigment, a solid photographic material, a solid cosmetic ingredient, a solid support material, a solid toner material, a solid grinding material, and a solid pharmaceutical agent.

8. The process of claim 1, wherein the solid substrate is a pharmaceutical agent.

9. The process of claim 8, wherein the pharmaceutical agent is a poorly water soluble or water insoluble drug.

10. The process of claim 8, wherein the pharmaceutical agent is selected from the group consisting of an anesthetic agent, an ace inhibiting agent, an antithrombotic agent, an anti-allergic agent, an antibacterial agent, an antibiotic agent, an anticoagulant agent, an anticancer agent, an antidiabetic agent, an antihypertension agent, an antifungal agent, an antihypotensive agent, an antiinflammatory agent, antimitotic agent, an antimigraine agent, an antiparkinson agent, an antirheumatic agent, an antithrombin, an antiviral agent, a beta blocking agent, a bronchospasmolytic agent, a calcium antagonist, a cardiovascular agent, a cardiac glycosidic agent, a carotenoid, a cephalosporin, a contraceptive agent, a cytostatic agent, a diagnostic imaging agent, a diuretic agent, an enkephalin, a fibrinolytic agent, a growth hormone, an immunosuppressant, an insulin, an interferon, a lactation inhibiting agent, a lipid-lowering agent, a lymphokine, a neurologic agent, a prostacyclin, a prostaglandin, a psycho-pharmaceutical agent, a protease inhibitor, a magnetic resonance diagnostic imaging agent, a reproductive control hormone, a sedative agent, a sex hormone, a somatostatin, a steroid hormonal agent, a vaccine, a vasodilating agent, and a vitamin.

11. The process of claim 8, wherein the pharmaceutical agent is selected from the group consisting of fenofibrate, nitrocamptothecin, and cyclosporin.

12. The process of claim 1, wherein the fluid carrier is selected from the group consisting of water, sterile water, water for injection, an aqueous solution of one or more salts, a solution of one or more aqueous buffers, aqueous phosphate buffered saline, sugar-containing water, an aqueous solution of one or more pharmaceutical excipients, an aqueous solution of one or more carbohydrates, an aqueous solution of one or more polymers, an aqueous solution of one or more surface active substance, a liquid surface active substance, ethanol, PEG-containing water, and mixtures of these carriers.

13. The process of claim 1, wherein the fluid carrier is sterile.

14. The process of claim 2, wherein the one or more than one surface active substance is selected from the group consisting of phospholipids, natural surfactants, nonionic surfactants, anionic surfactants, cationic surfactants, and colloidal clays.

15. The process of claim 2, wherein the one or more than one surface active substance is a phospholipid.

16. The process of claim 15, wherein the phospholipid is selected from the group consisting of egg lecithin, egg phosphatidylcholine, soy phosphatidylcholine, dimyristoyl phosphatidylglycerol, hydrogenated egg phosphatidylcholine, hydrogenated soybean phosphatidylcholine, and combinations thereof.

17. The process of claim 1, wherein the fluid carrier is selected from the group consisting of a gas, a liquefied compressed gas, a supercritical fluid, a supercritical fluid containing one or more dissolved excipients, and a supercritical fluid containing one or more surface active substances.

18. The process of claim 1, wherein the process is batchwise.

19. The process of claim 1, wherein the process is continuous.

20. The process of claim 1, wherein the first material is selected from the group consisting of silica, calcium carbonate, marble, magnesium carbonate, zinc carbonate, dolomite, lime, magnesia, barium sulfate, calcium sulfate, aluminum hydroxide, colloidal silica, zinc oxide, iron oxide, titanium oxide, a biodegradable polymer, a biocompatible polymer, a composite of biocompatible polymers, a composite of biodegradable polymers, a polymeric resin, an ion exchange resin, silicon dioxide, and glass bead.

21. The process of claim 1, wherein the portion of the milling bodies of the first material degraded is from 0.01% to 100%.

22. The process of claim 1, wherein the desired particle size S_p, is less than 10 micrometers.

23. The process of claim 1, wherein the desired particle size S_p, is less than 5 micrometers.

24. The process of claim 1, wherein the desired particle size S_p, is less than 2 micrometers.

25. The process of claim 1, wherein desired particle size S_p, is less than 1 micrometer.

26. The process of claim 1, wherein desired particle size S_p, is less than 500 nanometers.

27. The process of claim 1, wherein the plurality of milling bodies of first material is from 1:

1000 to 1000;

1 times the plurality of milling bodies of the second material.

28. The process of claim 1, wherein the plurality of milling bodies of first material is from 1:

100 to 100;

1 times the plurality of milling bodies of the second material.

29. The process of claim 1, wherein the plurality of milling bodies of first material is from 1:

10 to 10;

1 times the plurality of milling bodies of the second material.

30. The process of claim 1, wherein the media mill is maintained at a temperature below the melting point of the solid substrate.

31. The process of claim 1, wherein the small particles and small particulates are less than 2 micrometers in size.

32. The process of claim 1, wherein the small particles and small particulates are less than 1 micrometer in size.

33. The process of claim 1, wherein the small particles and small particulates are less than 0.5 micrometer in size.

34. The process of claim 1, wherein the small particles and small particulate are less than 0.4 micrometer in size.

35. The process of claim 1, wherein the separation employs a separating device selected from the group consisting of a filter, a separator in the media mill, a separator at an exit port in the media mill, a depth filter, a mesh, a screen, a sieve, a milk filter, and a bed of particles.

36. The process of claim 1, wherein the first material has a fracture toughness K_C1 and the second material has a fracture toughness K_C2, wherein K_C1 is less than K_C2.

37. The process of claim 36, wherein K_C1 is less than 1.

38. The process of claim 36, wherein KC₁ is less than 1.5.

39. The process of claim 36, wherein K_C1 is less than 2.

40. The process of claim 36, wherein K_C2 is at least 1.1 times larger than K_C1.

41. The process of claim 36, wherein K_C2 is at least 1.3 times larger than K_C1.

42. The process of claim 36, wherein K_C2 is at least 1.5 times larger than K_C1.

43. The process of claim 1, wherein the first material has a brittleness index B_1L and the second material has a brittleness index B_2L, wherein B_1L is less than B_2L, and B_1L and B_2L are less than about 5.5.

44. The process of claim 1, wherein the first material has a brittleness index B_1H and the second material has a brittleness index B_2H, wherein B_1H is greater than B_2H and both B_1H and B_2H are greater than about 5.5.

45. The process of claim 1, wherein the first material has a hardness H₁ and the second material has a hardness H₂, wherein H₁ is less than H₂.

46. The process of claim 1, wherein the milling bodies of the first material comprise an ion exchange resin.

47. The process of claim 1, wherein the milling bodies of the second material comprise an ion exchange resin.