Oxygen delivery agents and uses for the same

• US 20030120204A1
• Filed: 01/06/2003
• Published: 06/26/2003
• Est. Priority Date: 06/18/1997
• Status: Active Grant

• Current Assignee: Cerevast Therapeutics, Inc.
• Original Assignee: Evan C. Unger, Thomas Mccreery, Yunqiu Wu
• Inventors: Unger, Evan C., Wu, Yunqiu, McCreery, Thomas
• Granted Patent: US 7,105,151 B2
• Time in Patent Office: Days
• US Class Current: 604/82
• CPC Class Codes: A61K 41/0028 Disruption, e.g. by heat or ultrasounds, sonophysical or sonochemical activation, e.g. thermosensitive or heat-sensitive liposomes, disruption of calculi with a medicinal preparation and ultrasounds
• CPC Class Codes: A61K 47/544 Phospholipids
• CPC Class Codes: A61K 49/223 Microbubbles, hollow microspheres, free gas bubbles, gas microspheres
• CPC Class Codes: A61K 9/1271 Non-conventional liposomes, e.g. PEGylated liposomes, liposomes coated with polymers liposome as conjugate A61K47/6911

Abstract

The present invention describes, inter alia, oxygen delivery agents or blood substitutes comprising a fluorinated gas and a stabilizing material, uses for the oxygen delivery agents or blood substitutes, and apparatus for making and delivering the oxygen delivery agents or blood substitutes.

Claims

1. A method of delivering oxygen to a patient comprising administering to the patient a composition which comprises a fluorinated gas and a stabilizing material.

2. The method of claim 1, further comprising imaging the patient with diagnostic ultrasound to monitor the location of the composition.

3. The method of claim 2, further comprising applying therapeutic ultrasound to the patient to facilitate delivery of oxygen in a desired region of the patient.

4. The method of claim 1, wherein the composition further comprises an aqueous carrier.

5. The method of claim 1, wherein the composition further comprises oxygen.

6. The method of claim 5, wherein the oxygen is O₂.

7. The method of claim 5, wherein the fluorinated gas in the composition is present in an amount of about 15% to about 85% of the total amount of gas in the composition and the oxygen is present in an amount of about 85% to about 15% of the total amount of gas in the composition.

8. The method of claim 7, wherein the fluorinated gas in the composition is present in an amount of about 20% to about 80% of the total amount of gas in the composition and the oxygen is present in an amount of about 80% to about 20% of the total amount of gas in the composition.

9. The method of claim 1, wherein the fluorinated gas is selected from the group consisting of bromotrifluoroethane, chlorotrifluoromethane, dichlorodifluoromethane, dibromofluoromethane, chloropentafluoroethane, bromochlorodifluoromethane, dichloro-1,1,2,2-tetrafluoroethane, octafluorocyclobutane, decafluorobutane, hexafluoroethane, perfluoromethane, perfluoroethane, perfluoropropane, perfluorobutane, perfluoropropylene, perfluorocyclobutane, perfluoro-2-butyne, perfluoro-2-butene, perfluorobuta-1,3-diene, perfluoro n-propyl ethyl ether, perflouro diethyl ether, perfluoro methyl ethyl ether, perfluoro dimethyl ether, sulfur hexafluoride, selenium hexafluoride and perfluoropropionyl chloride.

10. The method of claim 9, wherein the fluorinated gas is selected from the group consisting of perfluoromethane, perfluoroethane, perfluoropropane, perfluorobutane, perfluorocyclobutane, perfluoro n-propyl ethyl ether, perflouro diethyl ether, perfluoro methyl ethyl ether, perfluoro dimethyl ether and sulfur hexafluoride.

11. The method of claim 10, wherein the fluorinated gas is selected from the group consisting of perfluoromethane, perfluoroethane, perfluoropropane and perfluorobutane.

12. The method of claim 11, wherein the fluorinated gas is selected from the group consisting of perfluoropropane and perfluorobutane.

13. The method of claim 12, wherein the fluorinated gas is perfluorobutane.

14. The method of claim 1, wherein the fluorinated gas has been converted to a gas from a gaseous precursor.

15. The method of claim 14, wherein the fluorinated gas that has been converted to a gas from a gaseous precursor is selected from the group consisting of 1-bromo-1,1,2,3,3,3-hexafluoropropane, bromoperfluoropropane, 2-chloro-1,1,1,4,4,4-hexafluoro-2-butene, 2-chloropentafluoro-1,3-butadiene, iodotrifluoroethylene, 1,1,2-trifluoro-2-chloroethane, 1,2-difluorochloroethane, 1,1-difluoro-2-chloroethane, 1,1-dichlorofluoroethane, 1-bromoethane, 1-fluorobutane, perfluoropentane, perfluorotetrahydropyran, perfluoromethyltetrahydrofuran, perfluoro t-butyl methyl ether, perfluoro n-butyl methyl ether, perfluoro isopropyl methyl ether, 1-bromo-nonafluorobutane, 1-chloro-1-fluoro-1-bromomethane, 1,1,1-trichloro-2,2,2-trifluoroethane, 1,2-dichloro-2,2-difluoroethane, 1,1-dichloro-1,2-difluoroethane, 1,2-dichloro-1,1,3-trifluoropropane, 1-bromoperfluorobutane, 1-bromo-2,4-difluorobenzene, 2-iodo-1,1,1-trifluoroethane, 5-bromovaleryl chloride, 1,3-dichlorotetrafluoroacetone, bromine pentafluoride, heptafluoro-2-iodopropane, 6-bromo-1-hexene, 2-bromo-2-nitropropane, 2-bromo-5-nitrothiophene, 2-bromopropene, 3-chloro-5,5-dimethyl-2-cyclohexane, 2-chloro-2-methylpropane, perfluoro-2-methyl-2-pentene, 1,1,1,3,3-pentafluoropentane, 3-fluorobenzaldehyde, 2-fluoro-5-nitrotoluene, 3-fluorostyrene, 3,5-difluoroaniline, 2,2,2-trifluoroethylacrylate, 3-(trifluoromethoxy)-acetophenone, 1,1,2,2,3,3,4,4-octafluorobutane, 1,1,1,3, 3-pentafluorobutane, tetradecaperfluoroheptane, dodecaperfluorocyclohexane, n-perfluorohexane, perfluoro-2-methyl-2-pentene, perfluorocyclohexane, perfluorobutylethyl ether, bis(perfluoroisopropyl) ether and bis(perfluoropropyl) ether.

16. The method of claim 15, wherein the fluorinated gas that has been converted to a gas from a gaseous precursor is selected from the group consisting of bromoperfluoropropane, perfluoropentane, perfluorocyclopentane, perfluorobutyl methyl ether, perfluoromethyl n-butyl ether, perfluoromethyl isopropyl ether, perfluoromethyl t-butyl ether, perfluorotetrahydropyran, and perfluoromethyltetrahydrofuran.

17. The method of claim 16, wherein the fluorinated gas that has been converted to a gas from a gaseous precursor is perfluoropentane.

18. The method of claim 1, wherein the stabilizing material is in a vesicular form.

19. The method of claim 1, wherein the stabilizing material is non-vesicular.

20. The method of claim 1, wherein the stabilizing material comprises a lipid, a protein or a polymer.

21. The method of claim 20, wherein the stabilizing material comprises a lipid.

22. The method of claim 21, wherein the lipid is a phospholipid or a fluorinated lipid.

23. The method of claim 1, wherein the stabilizing material comprises a surfactant.

24. The method of claim 23, wherein the surfactant is a fluorinated surfactant.

25. The method of claim 1, wherein the composition further comprises a fluorinated liquid compound.

26. The method of claim 25, wherein the fluorinated liquid compound is selected from the group consisting of perfluorohexane, perfluoroheptane, perfluorooctane, perfluorononane, perfluorodecane, perfluorododecane, perfluorodecalin, perfluorooctyliodide, perfluorooctylbromide, perfluorotributylamine, perfluorotripropylamine, perfluorobutyl ethyl ether, bis(perfluoroisopropyl) ether and bis(perfluoropropyl) ether.

111. The apparatus according to claim 10, wherein said pressure wave generating means comprises means for generating pressure waves in the ultrasonic frequency range.

112. The apparatus according to claim 111, wherein said pressure wave generating means comprises means for generating pressure waves in the approximately 20 KHz to 5 MHz frequency range.

27. An oxygen delivery agent comprising a composition which comprises a fluorinated gas and a stabilizing material.

28. The oxygen delivery agent of claim 27, further comprising an aqueous carrier.

29. The oxygen delivery agent of claim 27, wherein the composition further comprises oxygen.

30. The oxygen delivery agent of claim 29, wherein the oxygen is O₂.

31. The oxygen delivery agent of claim 29, wherein the fluorinated gas is present in an amount of about 15% to about 85% of the total amount of gas in the composition and the oxygen is present in an amount of about 85% to about 15% of the total amount of gas in the composition.

32. The oxygen delivery agent of claim 31, wherein the fluorinated gas is present in an amount of about 20% to about 80% of the total amount of gas in the composition and the oxygen is present in an amount of about 80% to about 20% of the total amount of gas in the composition.

33. The oxygen delivery agent of claim 27, wherein the fluorinated gas is selected from the group consisting of bromotrifluoroethane, chlorotrifluoromethane, dichlorodifluoromethane, dibromofluoromethane, chloropentafluoroethane, bromochlorodifluoromethane, dichloro-1,1,2,2-tetrafluoroethane, octafluorocyclobutane, decafluorobutane, hexafluoroethane, perfluoromethane, perfluoroethane, perfluoropropane, perfluorobutane, perfluoropropylene, perfluorocyclobutane, perfluoro-2-butyne, perfluoro-2-butene, perfluorobuta-1,3-diene, perfluoro n-propyl ethyl ether, perflouro diethyl ether, perfluoro methyl ethyl ether, perfluoro dimethyl ether, sulfur hexafluoride, selenium hexafluoride and perfluoropropionyl chloride.

34. The oxygen delivery agent of claim 33, wherein the fluorinated gas is selected from the group consisting of perfluoromethane, perfluoroethane, perfluoropropane, perfluorobutane, perfluorocyclobutane, perfluoro n-propyl ethyl ether, perflouro diethyl ether, perfluoro methyl ethyl ether, perfluoro dimethyl ether and sulfur hexafluoride.

35. The oxygen delivery agent of claim 34, wherein the fluorinated gas is selected from the group consisting of perfluoromethane, perfluoroethane, perfluoropropane and perfluorobutane.

36. The oxygen delivery agent of claim 35, wherein the fluorinated gas is selected from the group consisting of perfluoropropane and perfluorobutane.

37. The oxygen delivery agent of claim 36, wherein the fluorinated gas is perfluorobutane.

38. The oxygen delivery agent of claim 27, wherein the fluorinated gas has been converted to a gas from a gaseous precursor.

39. The oxygen delivery agent of claim 38, wherein the fluorinated gas that has been converted to a gas from a gaseous precursor is selected from the group consisting of 1-bromo-1,1,2,3,3,3-hexafluoropropane, bromoperfluoropropane, 2-chloro-1,1,1,4,4,4-hexafluoro-2-butene, 2-chloropentafluoro-1,3-butadiene, iodotrifluoroethylene, 1,1,2-trifluoro-2-chloroethane, 1,2-difluorochloroethane, 1,1-difluoro-2-chloroethane, 1,1-dichlorofluoroethane, 1-bromoethane, 1-fluorobutane, perfluoropentane, perfluorotetrahydropyran, perfluoromethyltetrahydrofuran, perfluoro t-butyl methyl ether, perfluoro n-butyl methyl ether, perfluoro isopropyl methyl ether, 1-bromo-nonafluorobutane, 1-chloro-1-fluoro-1-bromomethane, 1,1,1-trichloro-2,2,2-trifluoroethane, 1,2-dichloro-2,2-difluoroethane, 1,1-dichloro-1,2-difluoroethane, 1,2-dichloro-1,1,3-trifluoropropane, 1-bromoperfluorobutane, 1-bromo-2,4-difluorobenzene, 2-iodo-1,1,1-trifluoroethane, 5-bromovaleryl chloride, 1,3-dichlorotetrafluoroacetone, bromine pentafluoride, heptafluoro-2-iodopropane, 6-bromo-1-hexene, 2-bromo-2-nitropropane, 2-bromo-5-nitrothiophene, 2-bromopropene, 3-chloro-5,5-dimethyl-2-cyclohexane, 2-chloro-2-methylpropane, perfluoro-2-methyl-2-pentene, 1,1,1,3,3-pentafluoropentane, 3-fluorobenzaldehyde, 2-fluoro-5-nitrotoluene, 3-fluorostyrene, 3,5-difluoroaniline, 2,2,2-trifluoroethylacrylate, 3-(trifluoromethoxy)-acetophenone, 1,1,2,2,3,3,4,4-octafluorobutane, 1,1,1,3,3-pentafluorobutane, tetradecaperfluoroheptane, dodecaperfluorocyclohexane, n-perfluorohexane, perfluoro-2-methyl-2-pentene, perfluorocyclohexane, perfluorobutylethyl ether, bis(perfluoroisopropyl) ether and bis(perfluoropropyl) ether.

40. The oxygen delivery agent of claim 39, wherein the fluorinated gas that has been converted to a gas from a gaseous precursor is selected from the group consisting of bromoperfluoropropane, perfluoropentane, perfluorocyclopentane, perfluorobutyl methyl ether, perfluoromethyl n-butyl ether, perfluoromethyl isopropyl ether, perfluoromethyl t-butyl ether, perfluorotetrahydropyran, and perfluoromethyltetrahydrofuran.

41. The oxygen delivery agent of claim 40, wherein the fluorinated gas that has been converted to a gas from a gaseous precursor is perfluoropentane.

42. The oxygen delivery agent of claim 27, wherein the stabilizing material is in a vesicular form.

43. The oxygen delivery agent of claim 27, wherein the stabilizing material is non-vesicular.

44. The oxygen delivery agent of claim 27, wherein the stabilizing material comprises a lipid, a protein or a polymer.

45. The oxygen delivery agent of claim 44, wherein the stabilizing material comprises a lipid.

46. The oxygen delivery agent of claim 45, wherein the lipid is a phospholipid or a fluorinated lipid.

47. The oxygen delivery agent of claim 27, wherein the stabilizing material comprises a surfactant.

48. The oxygen delivery agent of claim 47, wherein the surfactant is a fluorinated surfactant.

49. The oxygen delivery agent of claim 27, wherein the composition further comprises a fluorinated liquid compound.

50. The oxygen delivery agent of claim 49, wherein the fluorinated liquid compound is selected from the group consisting of perfluorohexane, perfluoroheptane, perfluorooctane, perfluorononane, perfluorodecane, perfluorododecane, perfluorodecalin, perfluorooctyliodide, perfluorooctylbromide, perfluorotributylamine, perfluorotripropylamine, perfluorobutyl ethyl ether, bis(perfluoroisopropyl) ether and bis(perfluoropropyl) ether.

51. An apparatus for making an oxygen delivery agent, comprising:

a first vessel containing a stabilizing material;

a second vessel containing a fluorinated compound;

means for mixing said stabilizing material and said fluorinated compound so as to form a mixture;

a supply of oxygen; and

means for introducing oxygen from said supply into said mixture so as to form an oxygen delivery agent.

52. The apparatus according to claim 51, wherein said stabilizing material comprises a aqueous solution containing lipids, whereby said mixing means forms an aqueous solution containing lipids filled with said fluorinated compound, and wherein said oxygen introducing means causes said fluorinated compound filled lipids to become further filled with said oxygen.

53. The apparatus according to claim 51, wherein said mixing means comprises means for inducing turbulence in said mixture.

54. The apparatus according to claim 53, wherein said turbulence inducing means comprises a static mixer.

55. The apparatus according to claim 54, wherein said static mixer comprises a helical baffle disposed within a conduit through which said mixture flows.

56. The apparatus according to claim 51, wherein said mixing means comprises means for agitating said mixture.

57. The apparatus according to claim 51, wherein said mixing means comprises means for generating pressure waves directed toward said mixture.

58. The apparatus according to claim 57, wherein said pressure wave generating means comprises means for generating pressure waves in the ultrasonic frequency range.

59. The apparatus according to claim 58, wherein said pressure wave generating means comprises means for generating pressure waves in the approximately 20 KHz to 5 MHz frequency range.

60. The apparatus according to claim 57, wherein said pressure wave generating means comprises a transducer.

61. The apparatus according to claim 57, wherein said pressure wave generating means comprises a chamber, said chamber enclosing a conduit through which said mixture flows.

62. The apparatus according to claim 61, wherein said pressure wave generating means further comprises means for facilitating transmission of said pressure waves through said chamber.

63. The apparatus according to claim 62, wherein said pressure wave generating means further comprises a transducer, and wherein said pressure wave transmission facilitating means comprises a medium disposed within said chamber between said conduit and said transducer.

64. The apparatus according to claim 61, wherein said pressure wave generating means further comprises at least first and second transducers mounted on said chamber.

65. The apparatus according to claim 64, wherein said first transducer has means for operating at a frequency lower than said second transducer.

66. The apparatus according to claim 64, wherein said first and second transducers have overlapping focal zone, and wherein said first transducer has means for operating at a first frequency and said second transducer has means for operating at a second frequency, said second frequency being an integer multiple of said first frequency.

67. The apparatus according to claim 51, wherein said mixing means comprises means for bringing said fluorinated compound and said stabilizing material into contact with each other.

68. The apparatus according to claim 67, wherein said contacting means comprises a section of tubing having first and second branches in flow communication with said first and second vessels, respectively.

69. The apparatus according to claim 67, wherein said mixing means further comprises a static mixer.

70. The apparatus according to claim 69, wherein said mixing means further comprises a pressure transducer.

71. The apparatus according to claim 70, wherein said pressure transducer has means for operating in the ultrasonic frequency range.

72. The apparatus according to claim 51, further comprising means for heating said mixture.

73. The apparatus according to claim 72, wherein said heating means has means for heating said mixture to at least approximately 37°

C.

74. The apparatus according to claim 51, wherein one of said vessels is disposed within the other of said vessels.

75. The apparatus according to claim 74, further comprising means for releasing the contents of said one vessel into said other vessel.

76. The apparatus according to claim 74, wherein one of said vessels forms a headspace containing said supply of oxygen.

77. The apparatus according to claim 76, wherein said vessel forming said oxygen containing headspace is said one of said vessels that is disposed within the other of said vessels.

78. The apparatus according to claim 51, wherein said second vessel is disposed within said first vessel, and wherein said second vessel forms a headspace adjacent said fluorinated compound, said headspace containing said supply of oxygen.

79. The apparatus according to claim 78, further comprising means for rupturing said second vessel, thereby releasing said fluorinated compound and said oxygen into said second vessel.

80. The apparatus according to claim 51, wherein one of said vessels comprises a flexible bag.

81. The apparatus according to claim 51, wherein one of said vessels has means for preferentially rupturing in a localized area.

82. The apparatus according to claim 51, wherein at least one of said vessels comprises a first syringe.

83. The apparatus according to claim 82, wherein said first vessel comprises said first syringe.

84. The apparatus according to claim 83, wherein said second vessel comprises a second syringe.

85. The apparatus according to claim 83, wherein said second vessel comprises a flexible bag disposed within said first syringe.

86. The apparatus according to claim 51, further comprising means for evacuating said first and second vessels.

87. The apparatus according to claim 86, wherein said first vessel comprises a syringe, said syringe having a plunger, and wherein said evacuating means comprises means for driving said plunger.

88. The apparatus according to claim 87, wherein said means for driving said plunger comprises pressurized gas.

89. The apparatus according to claim 88, further comprising a third vessel, said third vessel containing said pressurized gas, and wherein said means for driving said plunger further comprises means for piercing said third vessel.

90. The apparatus according to claim 89, wherein said piercing means comprises a threaded joint.

91. The apparatus according to claim 86, wherein said first vessel comprises a syringe, said second vessel comprises a rupturable member disposed within said syringe, further comprising means for rupturing said rupturable member.

92. The apparatus according to claim 91, wherein said rupturable member comprises a flexible bag.

93. The apparatus according to claim 51, further comprising a conduit for delivering said oxygen delivery agent to a patient.

94. The apparatus according to claim 93, wherein said means for introducing said oxygen into said mixture comprises means for directing said oxygen from said supply into said conduit.

95. The apparatus according to claim 51, wherein said means for introducing said oxygen into said mixture comprises means for directing said oxygen from said supply into one of said first and second vessels.

96. The apparatus according to claim 95, wherein said oxygen supply comprises a third vessel, and wherein said means for directing said oxygen into one of said first and second vessels comprises means for piercing said third vessel.

97. The apparatus according to claim 96, wherein said means for piercing said third vessel comprises a threaded joint.

98. The apparatus according to claim 96, further comprising means for evacuating said one of said first and second vessels into which said oxygen is directed, said evacuating means comprising a third vessel containing a supply of pressurized gas.

99. The apparatus according to claim 98, wherein said one of said first and second vessel into which said oxygen is directed comprises a syringe, said syringe having a plunger, said evacuating means further comprising means for directing said pressurized gas to said plunger.

100. The apparatus according to claim 51, wherein said fluorinated compound in said second vessel is a fluorinated gas.

101. The apparatus according to claim 51, wherein said fluorinated compound in said second vessel is a fluorinated gaseous precursor.

102. The apparatus according to claim 101, further comprising means for converting said gaseous precursor to a gas.

103. The apparatus according to claim 102, wherein said means for converting said gaseous precursor to a gas comprises means for generating pressure waves directed toward said gaseous precursor.

104. The apparatus according to claim 103, wherein said pressure waves are generated at a frequency in the ultrasonic range.

105. The apparatus according to claim 103, wherein said pressure wave generating means comprises a first transducer.

106. The apparatus according to claim 105, wherein said pressure wave generating means further comprises a second transducer, and wherein said first transducer has means for operating at a first frequency and said second transducer has means for operating at a second frequency, said first frequency being lower than said second frequency.

107. The apparatus according to claim 106, wherein second frequency is an integer multiple of said first frequency.

108. The apparatus according to claim 51, wherein said oxygen delivery agent is in the form of a vesicle, and further comprising means for regulating the size of said vesicle.

109. The apparatus according to claim 108, wherein said sizing means comprises a filter.

110. The apparatus according to claim 108, wherein said sizing means comprises means for generating pressure waves.

113. The apparatus according to claim 110, wherein said pressure wave generating means comprises a transducer.

114. An apparatus for making an oxygen delivery agent, comprising:

a first vessel containing a stabilizing material;

a second vessel containing a fluorinated compound;

means for forming a mixture of said stabilizing material and said fluorinated compound;

means for generating ultrasonic pressure waves and directed said pressure waves toward said mixture.

115. The apparatus according to claim 114, wherein said mixture forms vesicles, and wherein said ultrasonic pressure generating means has means for regulating the size of said vesicles.

116. The apparatus according to claim 114, wherein said fluorinated compound comprises a gaseous precursor, and wherein said ultrasonic pressure generating means has means for converting said gaseous precursor to a gas.

117. An apparatus for making an oxygen delivery agent, comprising:

a syringe containing a stabilizing material;

a first vessel containing a fluorinated compound, said first vessel disposed within said syringe; and

means for evacuating said first vessel into said syringe so as to mix said fluorinated compound with said stabilizing material.

118. The apparatus according to claim 117, wherein said evacuating means comprises means for rupturing said second vessel.

119. The apparatus according to claim 118, wherein said rupturing means comprises means for pressurizing said syringe.

120. The apparatus according to claim 119, wherein said means for pressurizing said syringe comprises a pressurized fluid.

121. The apparatus according to claim 120, wherein said means for pressurizing said syringe comprises a second vessel containing said pressurized fluid and means for piercing said second vessel.

122. The apparatus according to claim 117, wherein said first vessel comprises a flexible bag.

123. An apparatus for making an oxygen delivery agent, comprising:

a first syringe containing a stabilizing material;

a second syringe containing a fluorinated compound;

means for simultaneously evacuating said first and second syringes;

means for mixing said stabilizing material and said fluorinated compound evacuated from said first and second syringes.

124. A method for making an oxygen delivery agent, comprising the steps of:

mixing a stabilizing material together with a fluorinated compound so as to form a mixture;

subjecting said fluorinated compound to pressure waves in the ultrasonic frequency range; and

introducing oxygen into one of said stabilizing material, said fluorinated compound, and said mixture.

125. The method according to claim 124, wherein the step of subjecting said fluorinated compound to pressure waves in the ultrasonic frequency range is performed prior to the mixing step.

126. The method according to claim 124, wherein the step of subjecting said fluorinated compound to pressure waves in the ultrasonic frequency range is performed subsequent to the mixing step.

127. The method according to claim 124, wherein the step of subjecting said fluorinated compound to pressure waves in the ultrasonic frequency range is performed during the mixing step.

128. The method according to claim 124, wherein said fluorinated compound is a gaseous precursor, and wherein the step of subjecting said fluorinated compound to pressure waves in the ultrasonic frequency range converts said gaseous precursor to a gas.

129. The method according to claim 124, wherein the step of subjecting said fluorinated compound to pressure waves in the ultrasonic frequency range comprises the step of subjecting said fluorinated compound to ultrasonic pressure waves at first and second frequencies, said second frequency being higher than said first frequency.

130. The method according to claim 129, wherein said second frequency is an integer multiple of said first frequency.

131. The method according to claim 124, wherein said oxygen is introduced into said fluorinated compound prior to said mixing.

132. The method according to claim 124, wherein said oxygen is introduced into said stabilizing material prior to said mixing.

133. The method according to claim 124, wherein said oxygen is introduced into said mixture after said stabilizing material and said fluorinated compound have been mixed.

134. The method according to claim 124, wherein said mixture comprises vesicles, and wherein the step of subjecting said fluorinated compound to pressure waves in the ultrasonic frequency range regulates the size of said vesicles.