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Last Updated: March 28, 2024

Details for Patent: 5,846,518


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Title: Gas mixtures useful as ultrasound contrast media contrast agents containing the media and method
Abstract:The invention relates to injectable media for ultrasonic echography in the form of microbubbles or microballoons comprising at least two biocompatible substances A and B (gaseous at the body temperature) forming a mixture which when in suspension with usual surfactants, additives and stabilisers provides useful ultrasound contrast agents. At least one of the components (B) in the mixture is a gas whose molecular weight is greater than 80 daltons and whose solubility in water is below 0.0283 ml per ml of water at standard conditions. The presence of the first component (B) in the contrast medium may vary between 0.5 and 41 volume percent. The other component (A) of the ultrasound contrast media is a gas or a mixture of gases whose molecular weight is below 80 daltons. The second component is present in a proportion of between 59-99.5% by vol., and is preferably chosen from oxygen, air, nitrogen, carbon dioxide or mixtures thereof. Gas mixtures described are found to be very effective as ultrasound contrast media. The invention also comprises a method of making the ultrasound contrast medium, the contrast agent and the ultrasound agent kit.
Inventor(s): Yan; Feng (Carouge, CH), Schneider; Michel (Troinex, CH), Brochot; Jean (Feigeres, CH)
Assignee: Bracco Research S.A. (CH)
Filing Date:May 01, 1997
Application Number:08/848,912
Claims:1. An injectable ultrasound contrast agent comprising a suspension of gas filled microbubbles in a physiologically acceptable aqueous carrier containing surfactants, additives and stabilizers, wherein the microbubbles are filled with a gas mixture of at least two biocompatible gases A and B in which at least one gas (B) present in an amount of between 0.5-41% by vol. has a molecular weight greater than 80 daltons and solubility in water below 0.0283 ml per ml of water at standard conditions, the balance of the mixture being gas A.

2. The ultrasound contrast agent of claim 1, wherein gas (B) is a fluorine-containing biocompatible gas.

3. The ultrasound contrast agent of claim 2, wherein the fluorine-containing gas is selected from the group consisting of SF.sub.6, CF.sub.4, C.sub.2 F.sub.6, C.sub.3 F.sub.6, C.sub.3 F.sub.8, C.sub.4 F.sub.6, C.sub.4 F.sub.8, C.sub.4 F.sub.10, C.sub.5 F.sub.10, C.sub.5 F.sub.12 and mixtures thereof.

4. The ultrasound contrast agent of claim 1 or 2, wherein gas A is selected from the group consisting of air, oxygen, nitrogen, carbon dioxide or mixtures thereof.

5. The ultrasound contrast agent of claim 1, wherein the surfactants comprise at least one film forming surfactant present in laminar and/or lamellar form and, optionally, hydrophilic stabilizers.

6. The ultrasound contrast agent of claim 5, wherein the film forming surfactant is a phospholipid.

7. The ultrasound contrast agent of claim 6, wherein the phospholipid is a saturated phospholipid selected from the group consisting of phosphatidic acid, phosphatidylcholine, phosphatidylethanolaminie, phosphatidylserine, phosphatidylglycerol, phosphatidylinositol, cardiolipin, sphingomyelin and mixtures thereof.

8. The ultrasound contrast agent of claim 6, wherein in addition to the phospholipid the aqueous carrier comprises copolymers of polyoxyethylene and polyoxypropylene, and glycerol.

9. The ultrasound contrast agent of claim 1, wherein the surfactants are soy bean oil, Tween and/or sorbitol.

10. The ultrasound contrast agent of claim 2, wherein the fluorine containing gas is SF.sub.6.

11. The ultrasound contrast agent of claim 10, wherein SF.sub.6 is present in an amount of 25-41% by vol. the balance being air.

12. The ultrasound contrast agent of claim 2, wherein the fluorine containing gas is CF.sub.4.

13. The ultrasound contrast agent of claim 2, wherein the fluorine containing gas is C.sub.2 F.sub.6.

14. The ultrasound contrast agent of claim 2, wherein the fluorine containing gas is C.sub.3 F.sub.6.

15. The ultrasound contrast agent of claim 2, wherein the fluorine containing gas is C.sub.3 F.sub.8.

16. The ultrasound contrast agent of claim 2, wherein the fluorine containing gas is C.sub.4 F.sub.8.

17. The ultrasound contrast agent of claim 16, wherein C.sub.4 F.sub.8 is present in an amount of 10-41% by vol. the balance being air.

18. The ultrasound contrast agent of claim 17, wherein C.sub.4 F.sub.8 is present in an amount of about 15% by vol. the balance being air.

19. The ultrasound contrast agent of claim 2, wherein the fluorine containing gas is C.sub.4 F.sub.10.

20. The ultrasound contrast agent of claim 2, wherein the fluorine containing gas is C.sub.5 F.sub.10.

21. The ultrasound contrast agent of claim 2, wherein the fluorine containing gas is C.sub.5 F.sub.12.

22. The ultrasound contrast agent of claim 21, wherein C.sub.5 F.sub.12 is present in an amount of 2.9-4.5% by vol. the balance being air.

23. The ultrasound contrast agent of claim 2, wherein the fluorine containing gas is a mixture of two or more fluorine containing gases.

24. The ultrasound contrast agent of claim 23, wherein the mixture contains C.sub.4 F.sub.8.

25. The ultrasound contrast agent of claim 24, wherein the mixture contains CF.sub.4.

26. The ultrasound contrast agent of claim 25, wherein the mixture consists of 5-15% vol. of C.sub.4 F.sub.8, 80% vol. of air, the balance being CF.sub.4.

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