Claims
- 1. A freeze-dried vesicle containing ultrasound contrast agent which agent contains a freeze-drying stabilizer in a weight ratio of said stabilizer to the vesicles in said agent of at least 200:1, and which agent is thermally stable at temperatures in excess of 20.degree. C.
- 2. A contrast agent as claimed in claim 1 wherein said stabilizer is selected from the group consisting of sucrose, maltose H.sub.2 O, trehalose, raffinose and stachyose.
- 3. A contrast agent as claimed in claim 1 wherein said stabilizer comprises sucrose.
- 4. A contrast agent as claimed in claim 1 wherein the vesicles in said agent contain a halocarbon gas or gas precursor.
- 5. A contrast agent as claimed in claim 4 wherein the halocarbon gas is a perfluoroalkane.
- 6. A contrast agent as claimed in claim 5 wherein the perfluoroalkane is selected from the group consisting of perfluorobutane and perfluoropentane.
- 7. A contrast agent as claimed in claim 1 wherein the vesicles have a membrane which comprises a phospholipid.
- 8. A process for the preparation of a thermally stable freeze-dried vesicle containing ultrasound contrast agent, which process comprises freeze-drying an aqueous dispersion comprising a vesicular ultrasound contrast agent and a freeze-drying stabilizer or mixture of stabilizers, wherein said stabilizer or mixture of stabilizers has a Tg value of at least 20.degree. C. and a Tg' value of -37.degree. C. or above, and in that said stabilizer or mixture of stabilizers is present in said dispersion at a weight ratio relative to said vesicular ultrasound contrast agent of at least 200:1.
- 9. A process as claimed in claim 8 wherein said aqueous dispersion contains from 1 to 50% by weight of said stabilizer.
- 10. A process as claimed in claim 8 wherein said vesicular contrast agent contains a halocarbon gas or gas precursor.
- 11. A process as claimed in claim 10 wherein said halocarbon gas is selected from the group consisting of perfluorobutane and perfluoropentane.
- 12. A process as claimed in claim 8 wherein said aqueous dispersion further contains a bulking agent.
- 13. A process as claimed in claim 12 wherein said bulking agent is a C.sub.3 polyol.
- 14. A process as claimed in claim 12 wherein said aqueous dispersion contains 3 to 10% by weight of said bulking agent.
- 15. An ultrasound contrast medium comprising an aqueous carrier medium, a freeze-drying stabilizer or mixture of stabilizers and an echogenic vesicular ultrasound contrast agent, wherein said stabilizer or mixture of stabilizers has a Tg value of at least 20.degree. C. and a Tg' value of -37.degree. C. or above, and in that said stabilizer or mixture of stabilizers is present in said medium at a weight ratio relative to said vesicular ultrasound contrast agent of at least 200:1.
- 16. A process for the preparation of a vesicle containing ultrasound contrast medium, said process comprising dispersing a freeze-dried contrast agent as claimed claim 1 in a physiologically tolerable aqueous dispersion medium.
- 17. A method of diagnosis of a mammal involving diagnostic ultrasound imaging, which method comprises administering a vesicle containing an ultrasound contrast medium which contains a freeze-drying stabilizer or mixture of stabilizers having a Tg value of at least 20.degree. C. and a Tg' value of -37.degree. C. or above at a weight ratio relative to the vesicles of at least 200:1 and performing ultrasound imaging.
- 18. A process for the storage or transportation of a vesicle containing ultrasound contrast agent wherein said agent is in freeze-dried form, which process comprises freeze-drying an aqueous dispersion comprising a vesicular ultrasound contrast agent and a freeze-drying stabilizer or mixture of stabilizers, wherein said stabilizer or mixture of stabilizers has a Tg value of at least 20.degree. C. and in that said stabilizer or mixture of stabilizers is present in said dispersion at a weight ratio relative to said vesicular ultrasound contrast agent of at least 200:1 and in that storage and transportation takes place without the use of cooling.
Priority Claims (3)
Number |
Date |
Country |
Kind |
9603466 |
Feb 1996 |
GBX |
|
9611894 |
Jun 1996 |
GBX |
|
9624919 |
Nov 1996 |
GBX |
|
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of PCT/GB97/00458, filed Feb. 19, 1997, and claims benefit of the U.S. provisional application Ser. No. 60/046,652, filed on May 16, 1997.
US Referenced Citations (6)
Foreign Referenced Citations (1)
Number |
Date |
Country |
06 211 645 |
Aug 1994 |
JPX |
Continuations (1)
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Number |
Date |
Country |
Parent |
PCTGB9700458 |
Feb 1997 |
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