US4920016A
Expired / Lapsed
US
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Liposomes with enhanced circulation time
Assignee: LIPSOME TECHNOLOGY Inc
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Filing: 1987-12-18
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Granted: 1990-04-24
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Expires: 2007-12-18
Abstract
Abstract A composition of liposomes which contain an entrapped pharmaceutical agent and are characterized by (a) liposome sizes predominantly between about 0.07 and 0.5 microns; (b) at least about 50 mole percent of a membrane-rigidifying lipid, such as sphingomyelin or neutral phospholipids with predominantly saturated acyl chains; and (c) between about 5-20 mole percent of a glycolipid selected from the group consisting of ganglioside GM 1 , saturated phosphatidylinositol, and monogalactosyl stearate. The liposomes show high blood/RES tissue distribution ratios, and are effective for drug administration to tumors via intravenous drug delivery.
Inventors
- 👤 Theresa M. Allen
- 👤 Alberto Gabizon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:16
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/10; A61K9/127; A61K9/1271; Y; Y10; Y10S; Y10S436/00; Y10S436/829; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2984
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
24 words
A composition comprising liposomes which contain an entrapped pharmaceutical agent and are characterized by: (a) liposome sizes predominantly between about 0.05 and 0.5 microns,
Claim 2
Dependent Claim
24 words
A composition comprising liposomes which contain an entrapped pharmaceutical agent and are characterized by: (a) liposome sizes predominantly between about 0.05 and 0.5 microns,
Claim 3
Dependent Claim
42 words
(b) liposomes having substantially homogeneous-phase bilayers composed at at least about 50 mole percent of a membrane-rigidifying lipid selected from the group consisting of sphingomyelin and neutral phospholipids with predominantly saturated acyl chains, and (c) between about 5-20 mole percent saturated phosphatidylinositol.
Claim 4
Dependent Claim
42 words
(b) liposomes having substantially homogeneous-phase bilayers composed at at least about 50 mole percent of a membrane-rigidifying lipid selected from the group consisting of sphingomyelin and neutral phospholipids with predominantly saturated acyl chains, and (c) between about 5-20 mole percent saturated phosphatidylinositol.
Claim 5
Dependent Claim
18 words
The composition of claim 1, wherein the liposomes are predominantly in the 0.07 to 0.12 micron size range.
Claim 6
Dependent Claim
30 words
The composition of claim 1, wherein the membrane-rigidifying lipid is brain sphingomyelin liposomes contain sphingomyelin and the liposomes contain sphingomyelin and phosphatidylcholine, at a mole ratio between 2:1 and 4:1.
Claim 7
Dependent Claim
16 words
The composition of claim 1, wherein the membrane-rigidifying lipid is predominantly phosphatidylcholine with saturated acyl chains.
Claim 8
Dependent Claim
89 words
In a therapeutic drug treatment in which a drug is administered intravenously in a suspension of liposomes in which the drug is entrapped and whose sizes are predominantly between about 0.05-0.5 microns, a method of extending the lifetime of liposomes in the bloodstream which comprises preparing the liposomes to contain: (a) substantially homogeneous-phase bilayers containing at least about 50 mole percent of a membrane-rigidifying lipid selected from the group consisting of sphingomyelin and neutral phospholipids with predominantly saturated acyl chains, and (b) between about 5-20 mole percent saturated phosphatidylinositol.
Claim 9
Dependent Claim
89 words
In a therapeutic drug treatment in which a drug is administered intravenously in a suspension of liposomes in which the drug is entrapped and whose sizes are predominantly between about 0.05-0.5 microns, a method of extending the lifetime of liposomes in the bloodstream which comprises preparing the liposomes to contain: (a) substantially homogeneous-phase bilayers containing at least about 50 mole percent of a membrane-rigidifying lipid selected from the group consisting of sphingomyelin and neutral phospholipids with predominantly saturated acyl chains, and (b) between about 5-20 mole percent saturated phosphatidylinositol.
Claim 10
Dependent Claim
20 words
The method of claim 5, wherein the liposomes contain sphingomyelin and phosphatidylcholine, at a mole ratio between 2:1 and 4:1.
Claim 11
Dependent Claim
16 words
The method of claim 5, wherein the membrane-rigidifying lipid is predominantly phosphatidylcholine with saturated acyl chains.
Claim 12
Dependent Claim
48 words
The method of claim 5, for use in tumor therapeutic drug treatment, wherein the amount of drug which is delivered to the tumor, as measured by the amount drug/tumor weight 24 hours after drug administration, is severalfold greater than that achievable by administering the drug in free form.
Claim 13
Dependent Claim
15 words
The method of claim 8, wherein drug which is entrapped in the liposomes is bleomycin.
Claim 14
Dependent Claim
16 words
The method of claim 8, wherein the drug which is entrapped in the liposomes is doxorubicin.
Claim 15
Dependent Claim
24 words
The method of claim 8, which further includes targeting the liposomes to the tumor by addition of tumor-specific binding molecules to the liposome surfaces.
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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) | 1993-04-23 | 1993-10-23 | 1994-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-23 | 1997-10-23 | 1998-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-23 | 2001-10-23 | 2002-04-24 | $7700.00 | Window Closed / Lapsed |