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US5518709A
Expired / Lapsed
US
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Preparation of diagnostic agents
Assignee: Quadrant Drug Delivery Ltd
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Filing: 1992-04-10
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Granted: 1996-05-21
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Expires: 2012-04-10
Abstract
Abstract PCT No. PCT/GB92/00643 Sec. 371 Date Mar. 15, 1993 Sec. 102(e) Date Mar. 15, 1993 PCT Filed Apr. 10, 1992 PCT Pub. No. WO92/18164 PCT Pub. Date Oct. 29, 1992.Microcapsules are prepared by a process comprising the steps of (i) spray-drying a solution or dispersion of a wall-forming material in order to obtain intermediate microcapsules and (ii) reducing the water-solubility of at least the outside of the intermediate microcapsules. Suitable wall-forming materials include proteins such as albumin and gelatin. The microcapsules have walls of 40-500 nm thick and are useful in ultrasonic imaging. The control of median size, size distribution and degree of insolubilization and cross-linking of the wall-forming material allows novel microsphere preparations to be produced.
Inventors
- 👤 Andrew D. Sutton
- 👤 Richard A. Johnson
- 👤 Peter J. Senior
- 👤 David Heath
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 13:54
CPC Classifications
A; A61; A61K; A61K49/00; A61K49/22; A61K49/222; A61K49/223; A61K49/225; A61K9/00; A61K9/14; A61K9/16; A61K9/1682; A61K9/1688; A61K9/1694; A61K9/48; A61K9/50; A61K9/5089; B; B01; B01J; B01J13/00; B01J13/02; B01J13/04; B01J13/043; B01J13/06; B01J13/14; Y; Y10; Y10S; Y10S516/00; Y10S516/924; Y10S516/928
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
113 words
A process of forming a stable, sterile powder comprising hollow microcapsules which are suspendable in a medium suitable for parenteral administration to form a suspension suitable for ultrasound imaging when administered parenterally, said process comprising: a) providing a solution of a protein selected from the group consisting of collagen, gelatin and serum albumin in a liquid; b) atomizing said solution through an orifice into a heated gas such that said liquid evaporates thereby forming hollow microcapsules of said protein having a diameter of from 0.05 to 20 μm; c) heating said microcapsules to reduce the water-solubility of said protein thereby obtaining said microcapsules as a stable powder; and d) rendering said powder sterile.
Claim 2
Dependent Claim
113 words
A process of forming a stable, sterile powder comprising hollow microcapsules which are suspendable in a medium suitable for parenteral administration to form a suspension suitable for ultrasound imaging when administered parenterally, said process comprising: a) providing a solution of a protein selected from the group consisting of collagen, gelatin and serum albumin in a liquid; b) atomizing said solution through an orifice into a heated gas such that said liquid evaporates thereby forming hollow microcapsules of said protein having a diameter of from 0.05 to 20 μm; c) heating said microcapsules to reduce the water-solubility of said protein thereby obtaining said microcapsules as a stable powder; and d) rendering said powder sterile.
Claim 3
Dependent Claim
20 words
A process according to claim 1, wherein said protein is human albumin prepared from serum or by recombinant DNA techniques.
Claim 4
Dependent Claim
13 words
A process according to claim 1 wherein the protein solution contains 10.0-30.0% protein.
Claim 5
Dependent Claim
18 words
A process according to claim 1 wherein the hollow microcapsules produced in step b) are 96-98% monomeric protein.
Claim 6
Dependent Claim
21 words
A process according to claim 1 wherein the hollow microcapsules produced in step c) contain no more than 5% monomeric protein.
Claim 7
Dependent Claim
25 words
A process according to claim 1 wherein said protein solution is atomized under conditions such that steps b) and c) are carried out substantially simultaneously.
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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) | 1999-05-21 | 1999-11-20 | 2000-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-05-21 | 2003-11-20 | 2004-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-05-21 | 2007-11-20 | 2008-05-21 | $7700.00 | Window Closed / Lapsed |