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US4837028A Expired / Lapsed US ⏱️ 0.0 years remaining

Liposomes with enhanced circulation time

Assignee: Liposome Technology Inc
•
Filing: 1986-12-24
•
Granted: 1989-06-06
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Expires: 2006-12-24
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Abstract

Abstract A composition of liposomes which contain an entrapped pharmaceutical agent and are characterized by: (a) liposome sizes predominantly between about 0.08 and 0.5 microns: (b) at least about 50 mole percent of a membrane-rigidifying component, such as sphingomyelin or neutral phospholipids with predominantly saturated acyl chains: and (c) between about 5-15 mole percent ganglioside G M1 . The liposomes show a blood/RES tissue distribution ratio, two hours after intravenous administration, which is substantially greater than the sum of the distribution ratios observed with similarly constructed liposome compositions containing the membrane-rigidifying agent alone and gangliosides alone. Also disclosed are methods for enhancing the blood/RES ratio of intravenously administered liposomes, and for assessing the effect of selected liposome components on in vivo uptake of liposomes by cells of the reticuloendothelial system (RES).

Inventors

  • 👤 Theresa M. Allen

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-23 16:16
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: 7
Claim 1
Independent Claim 72 words
A liposome composition having an enhanced blood circulation time when administered intravenously, comprising liposomes which contain an entrapped pharmaceutical agent and are characterized by: (a) liposome sizes predominantly between about 0.08 and 0.5 microns, (b) at least about 50 mole percent of a membrane-rigidifying lipid component selected from the group consisting of sphingomyelin and neutral phospholipids with predominantly saturated acyl chains, and (c) between about 5-15 mole precent ganglioside G M1 .
Claim 2
Dependent Claim 72 words
A liposome composition having an enhanced blood circulation time when administered intravenously, comprising liposomes which contain an entrapped pharmaceutical agent and are characterized by: (a) liposome sizes predominantly between about 0.08 and 0.5 microns, (b) at least about 50 mole percent of a membrane-rigidifying lipid component selected from the group consisting of sphingomyelin and neutral phospholipids with predominantly saturated acyl chains, and (c) between about 5-15 mole precent ganglioside G M1 .
Claim 3
Dependent Claim 22 words
The composition of claim 1, wherein the liposomes have a size distribution produced by liposome extrusion through a 0.4 micron polycarbonate filter.
Claim 4
Dependent Claim 16 words
The composition of claim 1, wherein the membrane-rigidifying agent is predominantly PC with saturated acyl chains.
Claim 5
Dependent Claim 80 words
In a therapeutic drug treatment in which a drug is administered intravenously in a suspension of liposomes whose sizes are predominantly between about 0.08-0.5 microns, a method of extending the lifetime of liposomes in the bloodstream which comprises preparing the liposomes to contain: (a) at least about 50 mole percent of a membrane-rigidifying component selected from the group consisting of sphingomyelin and neutral phospholipids with predominantly saturated acyl chains, and (b) between about 5-15 mole percent ganglioside G M1 .
Claim 6
Dependent Claim 80 words
In a therapeutic drug treatment in which a drug is administered intravenously in a suspension of liposomes whose sizes are predominantly between about 0.08-0.5 microns, a method of extending the lifetime of liposomes in the bloodstream which comprises preparing the liposomes to contain: (a) at least about 50 mole percent of a membrane-rigidifying component selected from the group consisting of sphingomyelin and neutral phospholipids with predominantly saturated acyl chains, and (b) between about 5-15 mole percent ganglioside G M1 .
Claim 7
Dependent Claim 26 words
The method of claim 4, wherein the liposomes are predominantly oligolamellar and have a size distribution produced by liposome extrusion through a 0.4 micron polycarbonate filter.

References Cited (Backward Citations)

US4598051A Cited
US4416872A Cited
US4684625A Cited
US4515736A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1992-06-05 1992-12-05 1993-06-06 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1996-06-05 1996-12-05 1997-06-06 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2000-06-05 2000-12-05 2001-06-06 $7700.00 Window Closed / Lapsed

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