Patent US5472442A successfully refreshed from Google Patents.
US4737323A
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US
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Liposome extrusion method
Assignee: Liposome Technology Inc
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Filing: 1986-02-13
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Granted: 1988-04-12
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Expires: 2006-02-13
Abstract
Abstract A suspension of liposomes whose sizes are predominantly greater than about 1 micron is passed through an asymmetric ceramic filter whose inner-surface pore size is about 1 micron. The processed liposomes have a selected average size of about 0.4 microns or less, depending on the number of filter cycles, and a narrow distribution.
Inventors
- 👤 Francis J. Martin
- 👤 Jacqueline K. Morano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:44
CPC Classifications
C; C04; C04B; C04B38/00; C04B38/0051; A; A61; A61K; A61K9/00; A61K9/10; A61K9/127; A61K9/1277; C04B2111/00; C04B2111/00474; C04B2111/00793; Y; Y10; Y10S; Y10S436/00; Y10S436/829; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2984
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
74 words
A method of producing a suspension of liposomes which have uniform sizes and a selected average size of less than about 0.4 microns, said method comprising: providing a suspension of heterogeneous-size liposomes containing a substantial portion with sizes greater than 1.0 micron in size, and passing the suspension under pressure through an asymmetric ceramic filter whose inner-surface pore size is greater than the desired average liposome size and no greater than about 1 micron.
Claim 2
Independent Claim
74 words
A method of producing a suspension of liposomes which have uniform sizes and a selected average size of less than about 0.4 microns, said method comprising: providing a suspension of heterogeneous-size liposomes containing a substantial portion with sizes greater than 1.0 micron in size, and passing the suspension under pressure through an asymmetric ceramic filter whose inner-surface pore size is greater than the desired average liposome size and no greater than about 1 micron.
Claim 3
Dependent Claim
18 words
The method of claim 1, wherein the liposome suspension is passed through the filter in an inside-to-outside direction.
Claim 4
Dependent Claim
14 words
The method of claim 1 wherein the membrane is a Ceraflow™ asymmetric ceramic filter.
Claim 5
Dependent Claim
36 words
The method of claim 1, for producing a suspension of liposomes having a selected average size of between about 0.3 and 0.4 microns, wherein said asymmetric filter has an inner-surface pore size of about 1 micron.
Claim 6
Dependent Claim
38 words
The method of claim 1, for producing a suspension of liposomes having a selected average size of between about 0.2 and 0.3 microns, wherein said asymmetric filter has an inner-surface pore size of about 0.45 microns in size.
Claim 7
Dependent Claim
44 words
The method of claim 5, for producing a suspension of liposome having a selected average size between about 0.2 and 0.3 microns, which further includes passing the suspension repeatedly through the filter, in an inside-to-outside direction, until the desired liposome average size is achieved.
Claim 8
Dependent Claim
19 words
The method of claim 6 which further includes alternately passing the suspension through the filter in an outside-to-inside direction.
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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) | 1991-04-12 | 1991-10-12 | 1992-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-12 | 1995-10-12 | 1996-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-12 | 1999-10-12 | 2000-04-12 | $7700.00 | Window Closed / Lapsed |