Magnetically Responsive Nanoparticle Therapeutic Constructs and Methods of Making and Using

• US 20110130616A1
• Filed: 07/17/2009
• Published: 06/02/2011
• Est. Priority Date: 06/18/2003
• Status: Active Grant

• Current Assignee: Swr&D Inc., Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Swr&D Inc.
• Inventors: Gibson, Donald D., Seeney, Charles E., Yuill, William A., Klostergaard, Jim
• Granted Patent: US 8,651,113 B2
• Time in Patent Office: Days
• US Class Current: 600/14
• CPC Class Codes: A61K 9/1641 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyethylene glycol, poloxamers
• CPC Class Codes: A61K 9/1676 having a drug-free core with discrete complete coating layer containing drug adsorbates of liquid drug formulations on inert powders without simultaneous granulation step A61K9/141; with further drug-free outer coating A61K9/5078; drug conjugated to non-active particles A61K47/6921
• CPC Class Codes: A61K 9/5094 Microcapsules containing magnetic carrier material, e.g. ferrite for drug targeting
• CPC Class Codes: A61N 2/12 using variable magnetic fields obtained by mechanical movement

Abstract

Magnetically responsive therapeutic carriers comprise nanoparticles including single-domain nanoparticles comprising magnetite and having an average particle size ranging between 1 and 50 nanometers, clusters of the single-domain nanoparticles, the clusters having an average cluster size ranging between 5 and 1000 nanometers, and mixtures of the two. The single-domain nanoparticles are encapsulated with a silica coating. A silane coupling agent is bonded to the silica coating and has a specific pendant functional group capable of selectively binding with the therapeutic. Preferably, the bond between the specific pendant functional group and the therapeutic is a covalent bond. The movement of magnetically responsive nanoparticle therapeutic constructs, with concentration and extravasation/endocytosis at a target site, such as cancerous tumors, uses a controllable magnetic field generator adapted to move the therapeutic constructs in three dimensions, and is enhanced using a repetitively-varying magnetic field. A method for treating cancer comprises administering and magnetically guiding a therapeutic construct comprising paclitaxel.

Claims

1. Magnetically responsive therapeutic carriers comprising:

magnetically responsive nanoparticles selected from the group consisting of;

(a) single-domain nanoparticles comprising magnetite and having an average particle size ranging between 1 and 50 nanometers,

(b) clusters of single-domain nanoparticles comprising magnetite, the particles having an average particle size ranging between 1 and 50 nanometers, the clusters having an average cluster size ranging between 5 and 1000 nanometers,

and mixtures of (a) and (b);

a silica coating encapsulating the single-domain nanoparticles; and

a first silane coupling agent bonded to the silica coating, the first silane coupling agent having a specific pendant functional group capable of selectively binding with the therapeutic.

2. The magnetically responsive therapeutic carriers of claim 1 wherein the single-domain nanoparticles comprise superparamagnetic magnetite nanoparticles.

3. The magnetically responsive therapeutic carriers of claim 1 wherein the magnetic moments of the single-domain nanoparticles within the cluster are substantially uniformly aligned.

4. The magnetically responsive therapeutic carriers of claim 1 wherein the pendant functional group on the first silane coupling agent is selected from the group consisting of ester, epoxy, amino, phenyl, carboxyl, and mercapto groups.

5. The magnetically responsive therapeutic carriers of claim 1 wherein the pendant functional group on the first silane coupling agent is an amino group.

6. The magnetically responsive therapeutic carriers of claim 1 wherein the carriers are fluorescent.

7. The magnetically responsive therapeutic carriers of claim 6 wherein the first silane coupling agent comprises N-(triethoxysilylpropyl)dansylamide or an aminosilane treated with 5-fluorescein isothiocyanate.

8. The magnetically responsive therapeutic carriers of claim 1 wherein the first silane coupling agent is selected from the group consisting of 3-aminopropyltrimethoxysilane, alkoxysilylpropyl ethylenediamine triacetic acid, 3-aminopropyltrimethoxysilane, alkoxysilylpropyl ethylenediamine triacetic acid trisodium salt, and 3-aminopropyltrimethoxysilane, alkoxysilylpropyl ethylenediamine triacetic acid tripotassium salt.

9. The magnetically responsive therapeutic carriers of claim 8 wherein the first silane coupling agent comprises N-(triethoxysilylpropypethylenediamine triacetic acid trisodium salt.

10. The magnetically responsive therapeutic carriers of claim 1 wherein the pendant functional group on the first silane coupling agent is a carboxyl group.

11. The magnetically responsive therapeutic carriers of claim 10 wherein the first silane coupling agent comprises an alkoxysilylpropyl-O-polyethylene oxide urethane containing monomer units of polyethylene glycol (PEG) terminating in an alcohol function which has been oxidized to a carboxyl group.

12. The magnetically responsive therapeutic carriers of claim 10 wherein the first silane coupling agent comprises N-(triethoxysilylpropyl)-O-polyethylene oxide urethane containing five monomer units of polyethylene glycol (PEG) terminating in an alcohol function which has been oxidized to a carboxyl group.

13. The magnetically responsive therapeutic carriers of claim 10 further comprising a therapeutic having one or more hydroxyl groups.

14. The magnetically responsive therapeutic carriers of claim 13 wherein the therapeutic is a taxane.

15. The magnetically responsive therapeutic carriers of claim 14 wherein the taxane is selected from the group consisting of paclitaxel, docetaxel and mixtures of the same.

16. The magnetically responsive therapeutic carriers of claim 13 wherein the therapeutic is selected from paclitaxel, polyglutamic acid-paclitaxel, and polyglutamic acid-docetaxel.

17. The magnetically responsive therapeutic carriers of claim 10 further comprising a therapeutic having one or more amine groups.

18. The magnetically responsive therapeutic carriers of claim 1, modified to bind to target cells, the carriers further comprising a therapeutic construct and an aptamer having a first site capable of selectively binding with the target cells.

19. The magnetically responsive therapeutic carriers of claim 18 wherein the aptamer is covalently bonded to the magnetically responsive therapeutic carrier.

20. The magnetically responsive therapeutic carriers of claim 18 wherein the aptamer further comprises a second site capable of selectively binding with the specific pendant functional group on the first silane coupling agent.

21. The magnetically responsive therapeutic carriers of claim 20 wherein the specific pendant functional group on the first silane coupling agent is a carboxyl group, and the aptamer second site is a hydroxyl or amine group.

22. The magnetically responsive therapeutic carriers of claim 18 further comprising a second silane coupling agent bonded to the silica coating and having a second specific pendant functional group capable of selectively binding with the aptamer.

23. The magnetically responsive therapeutic carriers of claim 18 wherein the aptamer is engineered to differentiate between normal and malignant tissue.

24. The magnetically responsive therapeutic carriers of claim 18 wherein the aptamer includes a modification for increasing the aptamer half-life.

25. The magnetically responsive therapeutic carriers of claim 24 wherein the aptamer modification is 2′

-fluorine-substituted pyrimidine or polyethylene glycol (PEG) linkage.

26. The magnetically responsive therapeutic carriers of claim 1 further comprising a polyethylene glycol (PEG) stealth agent bonded to the silica coating.

27. The magnetically responsive therapeutic carriers of claim 26 wherein the PEG stealth agent is alkoxysilylpropyl-O-polyethylene oxide urethane containing monomer units of polyethylene glycol (PEG).

28. The magnetically responsive therapeutic carriers of claim 1 wherein the first silane coupling agent comprises a pendant carboxyl group, and wherein the therapeutic carrier further comprises a polyethylene glycol (PEG) stealth agent bonded to the pendant carboxyl group.

29. The magnetically responsive therapeutic carriers of claim 1 further comprising a polyethylene glycol (PEG) stealth agent, and a second silane coupling agent bonded to the silica coating, wherein the (PEG) stealth agent is bonded to a pendant functional group on the second silane coupling agent.

30. A method of making a magnetically responsive therapeutic construct, comprising:

forming single-domain magnetically responsive iron oxide nanoparticles;

coating the iron oxide nanoparticles with a silicate material to form silica coated magnetically responsive nanoparticles;

treating the silica coated magnetically responsive nanoparticles by bonding to the silica coating a first silane coupling agent having specific pendant functional groups capable of selectively binding with a therapeutic, thereby forming nanoparticle therapeutic carriers;

combining the nanoparticle therapeutic carriers with a liquid containing the therapeutic to allow the specific pendant functional groups to bond with the therapeutic and form a therapeutic construct;

applying a first magnetic field to the liquid containing the therapeutic construct thereby separating the therapeutic construct from the liquid.

31. The method of claim 30 wherein the iron oxide nanoparticles comprise superparamagnetic magnetite nanoparticles.

32. The method of claim 30 wherein the silica coating step is conducted in a spray drying apparatus and comprises:

atomizing into droplets a suspension of the magnetically responsive nanoparticles and the silicate material, the silicate material selected from the group consisting of sodium silicate, lithium silicate, aluminum silicate, zirconium silicate, calcium silicate, and silicic acid;

exposing an effective portion of the droplets in the spray drying apparatus to a second magnetic field to encourage uniform alignment of the nanoparticle magnetic moments within each exposed droplet; and

contacting the droplets with a heated drying gas to form magnetically responsive nanoparticle clusters.

33. The method of claim 30 wherein the pendant functional group on the first silane coupling agent is selected from the group consisting of ester, epoxy, amino, phenyl, carboxyl, and mercapto groups.

34. The method of claim 33 wherein the pendant functional group on the first silane coupling agent is a carboxyl group.

35. The method of claim 34 wherein the step of treating the nanoparticles by bonding to the silica coating a first silane coupling agent includes bonding to the silica coating an alkoxysilylpropyl-O-polyethylene oxide urethane containing monomer units of polyethylene glycol (PEG) terminating in an alcohol function, and oxidizing the alcohol function to a carboxyl group.

36. The method of claim 35 wherein the alcohol function is oxidized with potassium permanganate.

37. The method of claim 35 wherein the alkoxysilylpropyl-O-polyethylene oxide urethane containing monomer units of polyethylene glycol (PEG) comprises N-(triethoxysilylpropyl)-O-polyethylene oxide urethane containing five monomer units of polyethylene glycol (PEG).

38. The method of claim 34 wherein the step of combining the nanoparticle therapeutic carriers with a liquid containing the therapeutic includes activating the carboxyl function on the silane coupling agent by reacting with a carbodiimide.

39. The method of claim 34 wherein the therapeutic comprises one or more hydroxyl groups for binding with the carboxyl group on the first silane coupling agent.

40. The method of claim 34 wherein the therapeutic a taxane is selected from the group consisting of paclitaxel, docetaxel and mixtures of paclitaxel and docetaxel.

41. The method of claim 34 wherein the therapeutic is a taxane selected from the group consisting of paclitaxel, polyglutamic acid-paclitaxel, and polyglutamic acid-docetaxel.

42. The method of claim 34 wherein the therapeutic comprises an amine group for binding with the carboxyl group on the first silane coupling agent.

43. The method of claim 34 wherein the therapeutic comprises a linked aptamer for selectively binding with target cells.

44. The method of claim 34 further comprising the step of combining the nanoparticle therapeutic carriers with a liquid containing an aptamer, the aptamer having a first site capable of selectively binding with specific target cells, and a second site capable of selectively binding with the pendant carboxyl group on the first silane coupling agent, wherein the aptamer is allowed to chemically bind to the pendant carboxyl group.

45. The method of claim 44 wherein the aptamer second site is a hydroxyl or amine group.

46. The method of claim 43 wherein the aptamer is engineered to differentiate between normal and malignant forms of the same tissue.

47. The method of claim 43 wherein the aptamer is modified with a 2′

-fluorine-substituted pyrimidine or polyethylene glycol (PEG) linkage.

48. The method of claim 43 further comprising the step of binding a polyethylene glycol (PEG) stealth agent to the silica coating.

49. A method for delivering a therapeutic to target cells within a body, the method comprising the following steps:

preparing magnetically responsive therapeutic constructs comprising;

magnetically responsive carrier nanoparticles selected from the group consisting of;

(a) single-domain nanoparticles comprising magnetite and having an average particle size ranging between 1 and 50 nanometers, (b) clusters of single-domain nanoparticles comprising magnetite, the particles having an average particle size ranging between 1 and 50 nanometers, the clusters having an average cluster ranging between 5 and 1000 nanometers, and mixtures of (a) and (b);

a silica coating encapsulating the single-domain nanoparticles;

a silane coupling agent bonded to the silica coating and having a specific pendant functional group capable of selectively binding with the therapeutic; and

the therapeutic chemically bonded to the silane coupling agent;

introducing the magnetically responsive therapeutic constructs into the body; and

moving the therapeutic constructs to the target cell using a controllable magnetic field generator adapted to move the carrier nanoparticles in three dimensions.

50. The method of claim 49 wherein the magnetically responsive nanoparticles comprise superparamagnetic nanoparticles.

51. The method of claim 49 wherein the specific pendant functional group on the silane coupling agent is a carboxyl group.

52. The method of claim 51 wherein the silane coupling agent comprises an alkoxysilylpropyl-O-polyethylene oxide urethane containing monomer units of polyethylene glycol (PEG) terminating in an alcohol function which has been oxidized to a carboxyl group.

53. The method of claim 51 wherein the therapeutic comprises one or more hydroxyl groups.

54. The method of claim 51 wherein the therapeutic comprises a taxane.

55. The method of claim 54 wherein the taxane is selected from the group consisting of paclitaxel, docetaxel and mixtures of the same.

56. The method of claim 54 wherein the therapeutic comprises a taxane selected from paclitaxel, polyglutamic acid-paclitaxel, and polyglutamic acid-docetaxel.

57. The method of claim 49 wherein the therapeutic constructs are introduced to the body systemically.

58. The method of claim 57 wherein the therapeutic constructs are administered to the body intravenously.

59. The method of claim 49 wherein the therapeutic constructs are introduced to a tumor in the body via an intra-tumor arterial route.

60. The method of claim 49 further comprising delivering the therapeutic constructs through a membrane adjacent the target cells.

61. The method of claim 60 wherein the membrane comprises a tumor wall.

62. The method of claim 60 wherein the magnetic field generator is controlled to produce a repetitively-varying magnetic field gradient.

63. The method of claim 62 wherein the magnetic field intensity oscillates on and off.

64. The method of claim 62 wherein the magnetic field has an oscillating directional component.

65. The method of claim 64 wherein the oscillating directional component is perpendicular to a direction the therapeutic constructs are to be moved.

66. The method of claim 62 wherein the magnetic field generator comprises an electromagnet, the method further comprising controlling an electrical switch to oscillate power to the electromagnet.

67. The method of claim 62 wherein the magnetic field generator comprises two pulsed electromagnets separated by a permanent magnet supplying at least about 50% of the magnetic field directed toward the target cells.

68. The method of claim 67 wherein the two electromagnets are directed parallel to the permanent magnet and wherein the controller is adapted to alternately pulse the electromagnets.

69. The method of claim 67 wherein the two electromagnets are directed at an angle relative to the permanent magnet direction and wherein the controller is adapted to alternately pulse the electromagnets.

70. The method of claim 62 wherein the magnetic field generator comprises three or more oscillating electromagnets surrounding and parallel to a permanent magnet supplying at least about 50% of the magnetic field.

71. The method of claim 49 wherein the specific pendant functional group on the silane coupling agent is a carboxyl group and the therapeutic is bonded to the silane coupling agent through ester linkages, the method further comprising the step of using the controllable magnetic field generator to hold the therapeutic constructs proximate the target cells for at least the time necessary for the ester linkages to be degraded hydrolytically (in vivo (catalyzed by esterases)) to release the therapeutic.

72. The method of claim 71 further comprising administering N-hydroxy succinimide to the target cells to activate release of the therapeutic.

73. A method for treating cancer in a subject, comprising administering to a subject having cancer a therapeutic construct comprising:

magnetically responsive nanoparticles selected from the group consisting of;

(a) single-domain nanoparticles comprising magnetite and having an average particle size ranging between 1 and 50 nanometers,

(b) clusters of single-domain nanoparticles comprising magnetite, the particles having an average particle size ranging between 1 and 50 nanometers, the clusters having an average cluster size ranging between 5 and 1000 nanometers,

and mixtures of (a) and (b);

a silica coating encapsulating the single-domain nanoparticles;

a first silane coupling agent bonded to the silica coating and having a pendant carboxyl groups capable of selectively binding with a therapeutic; and

the therapeutic comprising a taxane selected from the group consisting of paclitaxel, docetaxel and mixtures of the same.

74. The method of claim 73 wherein the silane coupling agent comprises an alkoxysilylpropyl-O-polyethylene oxide urethane containing monomer units of polyethylene glycol (PEG) terminating in an alcohol function which has been oxidized to a carboxyl group.

75. The method of claim 74 wherein the cancer is breast cancer, ovarian cancer, malignant melanoma, lung cancer, gastric cancer, prostate cancer, colon cancer, head and neck cancer, leukemia or Kaposi'"'"'s sarcoma.