US4529561A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for producing liposomes in selected size range
Assignee: University of California, San Diego
•
Filing: 1983-01-21
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Granted: 1985-07-16
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Expires: 2003-01-21
Abstract
Abstract Liposomes of uniform size are produced by forming liposomes in relatively random sizes, and extruding the liposomes under pressure through a uniform-pore-size membrane to force at least some of the liposomes into smaller sizes. Extrusion may be repeated to increase uniformity of the liposomes. The liposomes may contain an encapsulated drug.
Inventors
- 👤 C. Anthony Hunt
- 👤 Demetrios P. Papahadjopoulous
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:25
CPC Classifications
A; A61; A61K; A61K31/00; A61K31/70; A61K9/00; A61K9/10; A61K9/127; A61K9/1277; C; C07; C07H; C07H15/00; C07H15/20; C07H15/24; C07H15/252; Y; Y10; Y10S; Y10S436/00; Y10S436/829
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
36 words
A method for producing liposomes of uniform size comprising: forming liposomes in relatively random sizes; and, extruding the liposomes under pressure through a uniform-pore-size membrane to force at least some of the liposomes into smaller sizes.
Claim 2
Independent Claim
36 words
A method for producing liposomes of uniform size comprising: forming liposomes in relatively random sizes; and, extruding the liposomes under pressure through a uniform-pore-size membrane to force at least some of the liposomes into smaller sizes.
Claim 3
Dependent Claim
18 words
The method of claim 1 wherein the extruding includes repeating the extruding to increase uniformity of the liposomes.
Claim 4
Dependent Claim
15 words
The method of claim 1, wherein the liposomes are prepared to contain an encapsulated drug.
Claim 5
Independent Claim
50 words
A method for the production of liposomes of uniform size comprising forming liposomes in relatively random sizes, forcing the random sized liposomes through an orifice under pressure, and repeating the forcing by successively passing the liposomes through orifices of decreasing size to selectively force said liposomes into a uniform size.
Claim 6
Independent Claim
50 words
A method for the production of liposomes of uniform size comprising forming liposomes in relatively random sizes, forcing the random sized liposomes through an orifice under pressure, and repeating the forcing by successively passing the liposomes through orifices of decreasing size to selectively force said liposomes into a uniform size.
Claim 7
Dependent Claim
23 words
The method of claim 4 wherein at least one forcing is at high pressure, the high pressure being up to 3×10 4 psi.
Claim 8
Dependent Claim
20 words
The method of claim 4 wherein said liposomes are composed of lipids including phospholipids, macromolecules, cholesterols, amphiphiles, or mixtures thereof.
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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) | 1988-07-15 | 1989-01-14 | 1989-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-15 | 1993-01-14 | 1993-07-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-15 | 1997-01-14 | 1997-07-16 | $7700.00 | Window Closed / Lapsed |