US5376452A
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Induction of asymmetry in vesicles
Assignee: Elan Pharmaceuticals LLC
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Filing: 1993-10-06
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Granted: 1994-12-27
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Expires: 2013-10-06
Abstract
Abstract Methods are described for controlling the transbilayer distribution of ionizable lipids and proteins in vesicles. Control of the ion gradient of the exterior bathing medium in relation to that of the interior entrapped aqueous compartment of the vesicles induces migration of ionizable lipids or proteins to one or the other of the monolayers comprising the bilayer. This can result in an asymmetric distribution of the ionizable lipid or ionizable protein. The basic ionizable lipids, such as stearylamine and sphingosine, are sequestered into the inner monolayer when the liposome interior is acidic relative to the liposome exterior. Conversely, acidic ionizable lipids such as oleic acid and stearic acid are sequestered into the inner monolayer when the liposome interior is basic relative to the liposome exterior bathing solution. Likewise, phospholipids such as phosphatidylglycerol, phosphatidylinositol, and cardiolipin may also be sequestered into the inner monolayer in response to a relatively acidic exterior medium. Such vesicles may contain bioactive agents and may be administered to mammals including humans.
Inventors
- 👤 Michael J. Hope
- 👤 Pieter R. Cullis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:33
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/10; A61K9/127; A61K9/1277; A61K9/1278; Y; Y10; Y10S; Y10S436/00; Y10S436/829; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2984
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
41 words
A dehydrated liposome which comprises an outermost lipid bilayer having an asymmetric distribution of an ionizable lipid or ionizable protein between its inner and outer monolayers, wherein the asymmetric distribution is induced by a pH gradient across the outermost lipid bilayer.
Claim 2
Dependent Claim
41 words
A dehydrated liposome which comprises an outermost lipid bilayer having an asymmetric distribution of an ionizable lipid or ionizable protein between its inner and outer monolayers, wherein the asymmetric distribution is induced by a pH gradient across the outermost lipid bilayer.
Claim 3
Dependent Claim
11 words
The liposome of claim 1, wherein the ionizable lipid is acidic.
Claim 4
Dependent Claim
14 words
The liposome of claim 1, wherein the ionizable lipid or ionizable protein is basic.
Claim 5
Independent Claim
151 words
A method of monitoring the distribution of an amino group-containing ionizable lipid or ionizable protein between the inner and outer monolayers of the outer bilayer of a liposome comprising the ionizable lipid or ionizable protein which comprises: (a) preparing a liposome comprising the ionizable lipid or ionizable protein in a first aqueous buffer; (b) adding a labelling agent to the liposome, wherein the labelling agent reacts with an amino group on the ionizable lipid or ionizable protein so as to label the ionizable lipid or ionizable protein and wherein reaction between the labelling agent and the amino group is quantifiable; (c) altering the medium external to the liposome to obtain a second aqueous buffer which is acidic or basic relative to the first aqueous buffer; and (d) quantifying the amount of labelled ionizable lipid or ionizable protein in the inner and outer monolayers of the outer lipid bilayer of the liposome.
Claim 6
Independent Claim
151 words
A method of monitoring the distribution of an amino group-containing ionizable lipid or ionizable protein between the inner and outer monolayers of the outer bilayer of a liposome comprising the ionizable lipid or ionizable protein which comprises: (a) preparing a liposome comprising the ionizable lipid or ionizable protein in a first aqueous buffer; (b) adding a labelling agent to the liposome, wherein the labelling agent reacts with an amino group on the ionizable lipid or ionizable protein so as to label the ionizable lipid or ionizable protein and wherein reaction between the labelling agent and the amino group is quantifiable; (c) altering the medium external to the liposome to obtain a second aqueous buffer which is acidic or basic relative to the first aqueous buffer; and (d) quantifying the amount of labelled ionizable lipid or ionizable protein in the inner and outer monolayers of the outer lipid bilayer of the liposome.
Claim 7
Dependent Claim
14 words
The method of claim 4, wherein the labelling agent comprises trinitrobenzene sulphonic acid (TNBS).
Claim 8
Dependent Claim
11 words
The method of claim 4, wherein the ionizable lipid is acidic.
Claim 9
Dependent Claim
14 words
The method of claim 4, wherein the ionizable lipid or ionizable protein is basic.
Claim 10
Dependent Claim
28 words
The method of claim 4, wherein the ionizable lipid is acidic, the first aqueous buffer is a basic buffer and the second aqueous buffer is an acidic buffer.
Claim 11
Dependent Claim
20 words
The method of claim 8, wherein the pH of the first aqueous buffer is from about 8.0 to about 11.0.
Claim 12
Dependent Claim
16 words
The method of claim 9, wherein the pH of the first aqueous buffer is about 10.0.
Claim 13
Dependent Claim
20 words
The method of claim 8, wherein the pH of the second aqueous buffer is from about 2.0 to about 6.0.
Claim 14
Dependent Claim
16 words
The method of claim 11, wherein the pH of the second aqueous buffer is about 5.0.
Claim 15
Dependent Claim
31 words
The method of claim 4, wherein the ionizable lipid or ionizable protein is basic, the first aqueous buffer is an acidic buffer and the second aqueous buffer is a basic buffer.
Claim 16
Dependent Claim
20 words
The method of claim 13, wherein the pH of the first aqueous buffer is from about 2.0 to about 7.0.
Claim 17
Dependent Claim
16 words
The method of claim 14, wherein the pH of the first aqueous buffer is about 5.0.
Claim 18
Dependent Claim
20 words
The method of claim 13, wherein the pH of the second aqueous buffer is from about 7.0 to about 10.0.
Claim 19
Dependent Claim
16 words
The method of claim 16, wherein the pH of the second aqueous buffer is about 5.0.
References Cited (Backward Citations)
US3962429A
Cited
US3993754A
Cited
US4217344A
Cited
USRE31609E
Cited
US4145410A
Cited
US4224179A
Cited
US4235871A
Cited
US4193983A
Cited
US4241046A
Cited
US4411894A
Cited
US4438052A
Cited
US4389330A
Cited
US4485045A
Cited
EP0088046A2
Cited
US4619794A
Cited
US4522803A
Cited
US4515736A
Cited
US4588578A
Cited
US4713324A
Cited
WO1985000968A1
Cited
US4721612A
Cited
WO1986000238A1
Cited
US5008050A
Cited
WO1986001102A1
Cited
WO1986001103A1
Cited
US5077056A
Cited
US4762720A
Cited
US4663161A
Cited
US4975282A
Cited
WO1987000043A1
Cited
US4859319A
Cited
WO1987002219A1
Cited
US4916080A
Cited
US5204112A
Cited
US5252263A
Cited
US5089181A
Cited
US4978625A
Cited
US5192549A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-12-26 | 1998-06-27 | 1998-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-12-26 | 2002-06-27 | 2002-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-12-26 | 2006-06-27 | 2006-12-27 | $7700.00 | Window Closed / Lapsed |