US5316771A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of amphiphatic drug loading in liposomes by ammonium ion gradient
Assignee: Yissum Research Development Co of Hebrew University of Jerusalem
•
Filing: 1992-12-18
•
Granted: 1994-05-31
•
Expires: 2012-12-18
Abstract
Abstract An improved simple, efficient, safe, economical, and fast transmembrane loading procedure for efficient active loading of weak amphiphatic drugs into liposomes using the transmembrane gradient. The resulting liposomes loaded with the amphiphatic drug are stable and safe. A storagable form of loadable liposomes has extended period of stability. The reversed procedure is applicable for sustained release of liposome encapsulated drugs from ammonium liposomes.
Inventors
- 👤 Yechezkel Barenholz
- 👤 Gilad Haran
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:22
CPC Classifications
A; A61; A61K; A61K49/00; A61K49/22; A61K49/222; A61K49/227; 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: 3
Claim 1
Independent Claim
86 words
A method for loading into liposomes, an amphiphatic compound having a protonatable amine group, said method comprising: (a) preparing a suspension of liposomes having a greater concentration of ammonium ions inside the liposomes than outside the liposomes, where said preparing includes treating the liposomes to reduce their sizes, (b) adding said compound to the liposome suspension, and (c) by said adding, achieving uptake of the compound into the liposomes, to a final concentration of compound within the liposomes which is greater than that outside the liposomes.
Claim 2
Independent Claim
86 words
A method for loading into liposomes, an amphiphatic compound having a protonatable amine group, said method comprising: (a) preparing a suspension of liposomes having a greater concentration of ammonium ions inside the liposomes than outside the liposomes, where said preparing includes treating the liposomes to reduce their sizes, (b) adding said compound to the liposome suspension, and (c) by said adding, achieving uptake of the compound into the liposomes, to a final concentration of compound within the liposomes which is greater than that outside the liposomes.
Claim 3
Dependent Claim
30 words
The method of claim 1, wherein said preparing includes preparing the liposomes in the presence of an ammonium salt, and replacing ammonium ions outside the liposomes with a non-ammonium salt.
References Cited (Backward Citations)
US5204112A
Cited
US5192549A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-05-30 | 1997-11-29 | 1998-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-05-30 | 2001-11-29 | 2002-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-05-30 | 2005-11-29 | 2006-05-31 | $7700.00 | Window Closed / Lapsed |