Claims for Patent: 4,226,846

Summary for Patent: 4,226,846

Title:	Albumin microaggregates for radioactive scanning of reticuloendothelial systems
Abstract:	Microaggregates of a complex of (1) albumin, particularly human serum albumin and (2) a metal reducing agent, particularly a stannous reducing agent, preferably formed in the presence of a stabilizing ligand, which complex, when labelled with technetium-99m provides an excellent agent for imaging reticuloendothelial systems (RES), particularly the liver, spleen, and bone marrow; methods of making and using the same; a complex (physical or chemical) of technetium-99m with such microaggregates and methods of using such latter complex.
Inventor(s):	Saklad; Eugene L. (Sudbury, MA)
Assignee:	New England Nuclear Corporation (Boston, MA)
Application Number:	05/898,292
Patent Claims:	1. A composition for labelling with Tc-99m for radioactive imaging comprising microaggregates of albumin and a reducing metal. 2. A composition according to claim 1, said composition also comprising an additional stabilizing ligand for said reducing metal. 3. A composition for labelling with Tc-99m for radioactive imaging comprising microaggregates of albumin and a reducing metal, said composition also comprising an additional stabilizing ligand for said reducing metal selected from the group consisting of a phosphonate, a phosphate, an aminocarboxylate, a polyhydroxycarboxylate and a polycarboxylate. 4. A composition according to claim 3, said reducing metal being Sn.sup.++ and said ligand being a diphosphonate. 5. A composition according to claim 2, at least 90% of said microaggregates being not greater than 5 .mu.m in particle size. 6. A composition according to claim 5, at least 40% of said microaggregates being between 0.2 and 5 .mu.m in particle size. 7. A composition according to claim 5, at least 40% of said microaggregates being between 0.2 and 3 .mu.m. 8. A composition according to claim 7, said reducing metal being stannous and at least the major portion of said microaggregates being between 0.2 and 3 .mu.m in particle size. 9. A composition according to claim 5, no more than 50% of said microaggregates being less than 0.2 .mu.m in particle size. 10. A composition according to claim 2, said albumin being human serum albumin and said reducing metal being stannous. 11. A composition according to claim 10 wherein said composition is stabilized with undenatured albumin and a buffer. 12. A composition according to claim 11 also containing a non-ionic surfactant. 13. A composition according to claim 10, microaggregated at a pH between 4.5 and 9.5 but on the alkaline side of the apparent isoelectric point of said albumin. 14. A composition according to claim 13, said pH being between 5.4 and 7.0. 15. A composition according to claim 10, said composition being in the form of a freeze-dried solid. 16. A composition according to claim 1, at least 90% of said microaggregates being not greater than 5 .mu.m in particle size. 17. A composition for labelling with Tc-99m for radioactive imaging comprising microaggregates of albumin and a reducing metal, at least 90% of said microaggregates being not greater than 5 .mu.m in particle size, and at least 40% of said microaggregates being between 0.2 and 5 .mu.m in particle size. 18. A composition according to claim 17, no more than 50% of said microaggregates being less than 0.2 .mu.m in particle size. 19. A composition according to claim 1, said albumin being human serum albumin, said reducing metal being stannous, said microaggregates being microaggregated at a pH of 3.5-9.5, said composition being stabilized with undenatured human serum albumin and a buffer, and said stabilized composition being freeze-dried. 20. A radioactive imaging agent comprising Tc-99m labelled microaggregates of albumin and a reducing metal, wherein at least 90% of said microaggregates have a particle size not greater than 5 .mu.m and at least 40% of said microaggregates are between 0.2 and 5 .mu.m. 21. An agent according to claim 20 also comprising a stabilizing ligand for said reducing metal. 22. A radioactive imaging agent comprising Tc-99m labelled microaggregates of human serum albumin and a stannous reducing metal, said agent also comprising a stabilizing ligand for said reducing metal selected from the group consisting of phosphonates, phosphates, aminocarboxylates, polyhydroxycarboxylates and polycarboxylates. 23. A radioactive imaging agent comprising Tc-99m labelled microaggregates of albumin and a reducing metal, said agent also comprising a diphosphonate stabilizing ligand for said reducing metal. 24. An agent according to claim 23, said ligand being hydroxyethylene diphosphonate. 25. An agent according to claim 23, said ligand being methylene diphosphonate. 26. An agent according to claim 22, not substantially more than 50% of said microaggregates being less than 0.2 .mu.m. 27. An agent according to claim 21, at least 40% of said microaggregates being between 0.2 and 3 .mu.m. 28. An agent according to claim 21, the major portion of said microaggregates being between 0.2 and 3.0 .mu.m. 29. An agent according to claim 21, admixed with non-aggregated albumin, buffer and surfactant. 30. An agent according to claim 20, said albumin being human serum albumin, said reducing metal being stannous, at least 90% of said microaggregates having a particle size no greater than 5 .mu.m and not substantially more than 50% of said microaggregates being less than 0.2 .mu.m. 31. A radioactive imaging agent comprising Tc-99m labelled microaggregates of human serum albumin and a stannous reducing metal, at least 90% of said microaggregates having a particle size no greater than 5 .mu.m and not substantially more than 50% of said microaggregates being less than 0.2 .mu.m, said agent stabilized with non-aggregated human serum albumin and buffer, said microaggregates being microaggregated at a pH of 4.5-9.5 but on the alkaline side of the apparent isoelectric point of said albumin. 32. An agent according to claim 31, said pH being between 5.4 and 7.0. 33. An agent according to claim 31, said agent comprising methylene diphosphonate and said pH being between 5.6 and 6.5. 34. A method for making an agent for labelling with Tc-99m for radioactive imaging, said method comprising microaggregating albumin in the presence of a reducing metal. 35. A method according to claim 34, said microaggregation being carried out in the presence of a stabilizing ligand for said reducing metal. 36. A method for making an agent for labelling with Tc-99m for radioactive imaging, said method comprising microaggregating human serum albumin in the presence of a stannous reducing metal, said microaggregation being carried out in the presence of a stabilizing ligand for said reducing metal selected from the group consisting of a phosphonate, a phosphate, an aminocarboxylate, a polyhydroxycarboxylate and a polycarboxylate. 37. A method according to claim 35, said microaggregation being carried out at a pH at which at least 90% of the microaggregates have a particle size not greater than 5 .mu.m. 38. A method according to claim 37, said microaggregation being carried out at a pH at which not substantially more than 50% of the microaggregates have a particle size below 0.2 .mu.m. 39. A method according to claim 37, said aggregation being carried out at a pH at which at least 40% have a particle size between 0.2 and 5 .mu.m. 40. A method according to claim 37, said aggregation being carried out at a pH at which at least 40% of the microaggregates have a particle size between 0.2 and 3 .mu.m. 41. A method according to claim 37, said aggregation being carried out at a pH at which at least the major portion of the microaggregates have a particle size between 0.2 and 3 .mu.m. 42. A method according to claim 35, said aggregation being carried out at a pH between 4.5 and 9.5 but on the alkaline side of the apparent isoelectric point of said albumin. 43. A method according to claim 42, said pH being between 5.4 and 7.0. 44. A method according to claim 36, said ligand being a diphosphonate. 45. A method according to claim 36, said ligand being hydroxyethylene diphosphonate. 46. A method according to claim 36, said ligand being methylene diphosphonate. 47. A method according to claim 46, said microaggregates being carried out by heating at a pH of 5.4 to 6.6, at which at least 90% of the microaggregates have a particle size not greater than 5 .mu.m and at least 40% have a particle size between 0.2 and 3 .mu.m, said reducing metal being stannous and said albumin being human serum albumin. 48. A method according to claim 34, said microaggregation being carried out by passing a solution of undenatured human serum albumin and said reducing metal through a plurality of sequentially arranged heat exchangers in a semi-continuous manner. 49. A method according to claim 34, said reducing metal being stannous and said albumin being human serum albumin, said aggregation being carried out at a pH at which at least 90% of the microaggregates have a particle size not greater than 5 .mu.m and not substantially more than 50% have a particle size below 0.2 .mu.m. 50. A method according to claim 49, said microaggregation being carried out by heating at a pH between 4.5 and 9.5 but on the alkaline side of the apparent isoelectric point of said albumin at which at least the major portion of said microaggregates have a particle size between 0.2 .mu.m and 3.0 .mu.m. 51. A method according to claim 50, said pH being between 5.4 and 7.0. 52. A method according to claim 50, said pH being between 5.4 and 6.6 53. A method according to claim 34, said aggregation being carried out by heating albumin and said reducing metal by radiofrequency heating. 54. A method according to claim 34, said aggregation being carried out by heating albumin and said reducing metal by microwave heating. 55. A method according to claim 34, said aggregation being carried out by heating albumin and said reducing metal by induction heating. 56. A method of imaging the RES of a primate comprising injecting into the primate Tc-99m-labelled microaggregates of HSA and a reducing metal to concentrate said Tc-99m-labelled microaggregates in the RES. 57. A method according to claim 56, said composition containing a stabilizing ligand for said reducing metal. 58. A method for imaging the RES of a primate comprising injecting into the primate a composition comprising Tc-99m-labelled microaggregates of HSA and a stannous reducing metal to concentrate said Tc-99m-labelled microaggregates in the RES, said composition containing a diphosphonate stabilizing ligand for said reducing metal. 59. A method according to claim 58, at least 90% of said microaggregates having a particle size not greater than 5 .mu.m and at least 40% have a particle size between 0.2 and 3 .mu.m. 60. A preaggregated bulk, containing human serum albumin to be aggregated to microaggregates for radioactive labelling for use as an RES imaging agent, comprising a solution of unaggregated and undenatured human serum albumin, reducing metal and stabilizing ligand for said reducing metal, said bulk having a pH of between 4.5 and 9.5 but on the alkaline side of the isoelectric point of said albumin, the amount of ligand being sufficient to stabilize said stannous ions and prevent precipitation thereof before microaggregation but insufficient to provide any substantial non-RES target seeking properties when the microaggregates subsequently formed from said bulk are radioactively labelled and utilized for RES imaging. 61. A bulk according to claim 60, said pH being between 5.4 and 7.0. 62. A bulk according to claim 61, said reducing metal being stannous. 63. A preaggregated bulk containing human serum albumin to be aggregated to microaggregates for radioactive labelling for use as an RES imaging agent, comprising a solution of unaggregated and undenatured human serum albumin, stannous reducing metal and stabilizing ligand for said reducing metal, said bulk having a pH of between 5.6 and 6.5 but on the alkaline side of the isoelectric point of said albumin, the amount of ligand being sufficient to stabilize said stannous ions and prevent precipitation thereof before microaggregation but insufficient to provide any substantial non-RES target seeking properties when the microaggregates subsequently formed from said bulk are radioactively labelled and utilized for RES imaging, said ligand being a diphosphonate selected from the group consisting of methylene diphosphonate and hydroxyethylene diphosphonate. 64. A method for making an agent for labelling with Tc-99m for radioactive imaging, said method comprising microaggregating albumin in the presence of a reducing metal, at a pH between 3.5 and 9.5 but at a pH away from the apparent isoelectric point of said albumin. 65. A method according to claim 64 wherein said reducing metal is stannous and said albumin is human serum albumin, said step of microaggregating comprising heating said albumin and said reducing agent at said pH, thus forming microaggregates at least a major portion of which have a particle size between 0.2 .mu.m and 5.0 .mu.m, and at least 90% of which have a particle size not greater than 5.0 .mu.m.

Details for Patent 4,226,846

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Grifols Therapeutics Llc	ALBUKED, PLASBUMIN-20, PLASBUMIN-25, PLASBUMIN-5	albumin (human)	For Injection	101138	10/21/1942		2040-01-28
Baxalta Us Inc.	BUMINATE, FLEXBUMIN	albumin (human)	Injection	101452	03/03/1954		2040-01-28
Csl Behring Ag	ALBURX	albumin (human)	Injection	102366	07/23/1976		2040-01-28
Grifols Biologicals Llc	ALBUTEIN	albumin (human)	Injection	102478	08/15/1978		2040-01-28
Instituto Grifols, S.a.	HUMAN ALBUMIN GRIFOLS	albumin (human)	Injection	103352	02/17/1995		2040-01-28