US4935171A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for vesicle formation
Assignee: Nexstar Pharmaceuticals Inc
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Filing: 1989-01-27
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Granted: 1990-06-19
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Expires: 2009-01-27
Abstract
Abstract A single-vessel method is provided for preparing liposomes in commercial quantities by forming a homogeneous and uniform lipid film in a thin-film evaporator by evaporation of the organic solvent, followed by in situ hydration of the film in an aqueous phase by agitation with the rotor.
Inventors
- 👤 Kevin R. Bracken
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:36
CPC Classifications
B; B01; B01D; B01D1/00; B01D1/22; B01D1/222; B01D1/223; B01D1/225; A; A61; A61K; A61K9/00; A61K9/10; A61K9/127; A61K9/1277; Y; Y10; Y10S; Y10S436/00; Y10S436/829
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
133 words
A batch method for the formation of liposomes, comprising the steps (a) introducing a mixture comprising amphiphilic lipid material and an organic solvent in which the lipid is soluble into a chamber having a cylindrical interior heat transfer wall which transfers heat between the chamber and a thermal exchange jacket, a rotatable shaft disposed coaxially with respect to the wall, and at least one rotor blade secured to the rotatable shaft for rotation therewith and extending radially therefrom into a spaced, film-forming relationship with the wall; (b) forming a film of the lipid material on the wall by rotation of the blade and evaporation of the liquid; (c) introducing an aqueous phase into the chamber; and (d) hydrating the film by rotating the blade at a speed which is sufficient to form liposomes.
Claim 2
Dependent Claim
133 words
A batch method for the formation of liposomes, comprising the steps (a) introducing a mixture comprising amphiphilic lipid material and an organic solvent in which the lipid is soluble into a chamber having a cylindrical interior heat transfer wall which transfers heat between the chamber and a thermal exchange jacket, a rotatable shaft disposed coaxially with respect to the wall, and at least one rotor blade secured to the rotatable shaft for rotation therewith and extending radially therefrom into a spaced, film-forming relationship with the wall; (b) forming a film of the lipid material on the wall by rotation of the blade and evaporation of the liquid; (c) introducing an aqueous phase into the chamber; and (d) hydrating the film by rotating the blade at a speed which is sufficient to form liposomes.
Claim 3
Dependent Claim
14 words
The method of claim 1 in which the amphiphilic lipid material includes a phospholipid.
Claim 4
Dependent Claim
26 words
The method of claim 1 or 2 which further includes the step of drying the lipid film prior to introducing the aqueous phase into the chamber.
Claim 5
Dependent Claim
34 words
The method of claim 3 in which the chamber further includes a fluid feed inlet and a fluid outlet, each in fluid communication with the chamber and being disposed outside of the film-forming zone.
Claim 6
Dependent Claim
37 words
The method of claim 3 in which the chamber further includes a fluid feed inlet and a fluid outlet, the fluid outlet being disposed in a planar end of the closed chamber outside of the film-forming zone.
Claim 7
Dependent Claim
28 words
The method of claim 3 wherein the fluid outlet comprises a valve which provides a planar surface which is flush with the planar end of the closed chamber.
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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) | 1993-06-18 | 1993-12-18 | 1994-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-18 | 1997-12-18 | 1998-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-18 | 2001-12-18 | 2002-06-19 | $7700.00 | Window Closed / Lapsed |