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US5233995A
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Encapsulated particles useful as contrast agents in ultrasound and x-ray imaging compositions and methods
Assignee: GE Healthcare AS
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Filing: 1991-11-21
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Granted: 1993-08-10
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Expires: 2011-11-21
Abstract
Abstract Stable particles comprising a core consisting of a water-insoluble ester or amide of 3,5-diacetamido-2,4,6-triiodobenzoic acid encapsulated with methyl cellulose, such particles having an average particle size of less than about 10 μm, dispersions containing such particles, and methods for the preparation thereof are disclosed. The particles are particularly useful as contrast agents for use in x-ray and ultrasound diagnostic imaging compositions and methods.
Inventors
- 👤 Joseph S. Yudelson
- 👤 Robert O. James
- 👤 Denis M. Bailey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 06:50
CPC Classifications
A; A61; A61K; A61K49/00; A61K49/22; A61K49/222; A61K49/225; A61K49/04; A61K49/0433; A61K49/0447; A61K49/0461; A61K49/0476; A61K49/0485; A61K49/049
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
47 words
Stable particles comprising 50 to 90 percent by weight of a core consisting of a water insoluble ester or amide of 3,5-diacetamido-2,4,6-triiodobenzoic acid irreversibly encapsulated with 10 to 50 percent by weight of methyl cellulose, said particles having an average particle size of less than 10 μm.
Claim 2
Dependent Claim
47 words
Stable particles comprising 50 to 90 percent by weight of a core consisting of a water insoluble ester or amide of 3,5-diacetamido-2,4,6-triiodobenzoic acid irreversibly encapsulated with 10 to 50 percent by weight of methyl cellulose, said particles having an average particle size of less than 10 μm.
Claim 3
Dependent Claim
39 words
The particles of claim 1 wherein said water insoluble ester or amide has the structural formula: ##STR3## wherein R is OR 1 or ##STR4## R 1 is alkyl; and R 2 and R 3 are independently H or alkyl.
Claim 4
Dependent Claim
19 words
The particles of claim 1 wherein said particles have an average particle size of less than about 2 μm.
Claim 5
Dependent Claim
16 words
The particles of claim 1 wherein said core has a diameter of less than 1 μm.
Claim 6
Dependent Claim
16 words
The particles of claim 1 wherein said core consists of the ethyl ester of 3,5-diacetamido-2,4,6-triiodobenzoic acid.
Claim 7
Dependent Claim
14 words
A stable dispersion comprising the particles of claim 1 and an aqueous dispersion medium.
Claim 8
Dependent Claim
26 words
An ultrasound contrast composition comprising the particles of claim 1 in an amount effective to enhance the contrast of an ultrasound image, and a carrier therefor.
Claim 9
Dependent Claim
30 words
A method for ultrasound diagnostic imaging which comprises administering to the body of a test subject an effective contrast producing amount of the ultrasound contrast composition defined in claim 7.
Claim 10
Dependent Claim
26 words
An x-ray contrast composition comprising the particles of claim 1 in an amount effective to enhance the contrast of an x-ray image, and a carrier therefor.
Claim 11
Dependent Claim
30 words
A method for x-ray diagnostic imaging which comprises administering to the body of a test subject an effective contrast producing amount of the x-ray contrast composition defined in claim 9.
Claim 12
Independent Claim
101 words
A method of preparing particles comprising 50 to 90 percent by weight of a core consisting of a water insoluble ester or amide of 3,5-diacetamido-2,4,6-triiodobenzoic acid irreversibly encapsulated with 10 to 50 percent by weight of methyl cellulose, said particles having an average particle size of less than 10 μm, said method comprising the steps of: forming a first solution of an ester or amide of 3,5-diacetamido-2,4,6-triiodobenzoic acid in a water-miscible solvent; forming a second solution comprising methyl cellulose and water; mixing said first and second solutions; sonicating said mixture so as to produce a stable dispersion; and isolating said particles.
Claim 13
Independent Claim
101 words
A method of preparing particles comprising 50 to 90 percent by weight of a core consisting of a water insoluble ester or amide of 3,5-diacetamido-2,4,6-triiodobenzoic acid irreversibly encapsulated with 10 to 50 percent by weight of methyl cellulose, said particles having an average particle size of less than 10 μm, said method comprising the steps of: forming a first solution of an ester or amide of 3,5-diacetamido-2,4,6-triiodobenzoic acid in a water-miscible solvent; forming a second solution comprising methyl cellulose and water; mixing said first and second solutions; sonicating said mixture so as to produce a stable dispersion; and isolating said particles.
Claim 14
Dependent Claim
16 words
The method of claim 11 wherein the temperature of said mixture is at least 60° C.
Claim 15
Dependent Claim
19 words
The method of claim 11 wherein the viscosity of said methyl cellulose solution is less than about 200 cp.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-09 | 1997-02-08 | 1997-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-09 | 2001-02-08 | 2001-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-09 | 2005-02-08 | 2005-08-10 | $7700.00 | Window Closed / Lapsed |