US4797234A
Expired / Lapsed
US
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Production of sustained release composition from salt-form reactants
Assignee: Temple University
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Filing: 1987-06-19
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Granted: 1989-01-10
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Expires: 2007-06-19
Abstract
Abstract Sustained-released delivery forms comprising the reaction product of a Lewis acid salt with a Lewis base salt at the phase interface of their respective aqueous and non-aqueous solution to form an anisotropic high molecular weight salt of the acid and base and a neutral salt of the inorganic cation and anion in what is termed a "double decomposition" or "salt exchange" reaction.
Inventors
- 👤 Tully J. Speaker
- 👤 Tycho J. Speaker
- 👤 John H. Collett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:38
CPC Classifications
C; C07; C07K; C07K14/00; A; A01; A01N; A01N25/00; A01N25/26; A01N25/28; A61; A61K; A61K9/00; A61K9/48; A61K9/50; A61K9/5005; A61K9/5021; A61K9/5026; A61K9/5036; A61K9/5042; A61K9/5047; A61K9/5089; B; B01; B01J; B01J13/00; B01J13/02; B01J13/06; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2984; Y10T428/2985; Y10T428/2989
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
110 words
A method for producing a microcapsule comprising an anisotropic salt film for the gradual release of an encapsulated core material, consisting essentially of reacting (a) a partially hydrophilic, partially lipophilic polyfunctional Lewis acid salt in aqueous medium; and (b) a core material and a Lewis base salt in a water-immiscible, slightly polar, organic solvent for the base; in the form of an emulsion consisting essentially of a continuous aqueous phase of Lewis acid salt and water, and a discontinuous droplet phase of core material, Lewis base salt, and organic solvent, to form an anisotropic Lewis acid/Lewis base salt film semipermeable to and encapsulating the core material, and a neutral salt.
Claim 2
Independent Claim
110 words
A method for producing a microcapsule comprising an anisotropic salt film for the gradual release of an encapsulated core material, consisting essentially of reacting (a) a partially hydrophilic, partially lipophilic polyfunctional Lewis acid salt in aqueous medium; and (b) a core material and a Lewis base salt in a water-immiscible, slightly polar, organic solvent for the base; in the form of an emulsion consisting essentially of a continuous aqueous phase of Lewis acid salt and water, and a discontinuous droplet phase of core material, Lewis base salt, and organic solvent, to form an anisotropic Lewis acid/Lewis base salt film semipermeable to and encapsulating the core material, and a neutral salt.
Claim 3
Dependent Claim
27 words
The method of claim 1 wherein the organic solvent is selected from the group consisting of bromoform, chloroform, dichloromethane, dichloroethane, diethyl ether, diisopropyl ether, methylethylketone and nitrobenzene.
Claim 4
Dependent Claim
11 words
The method of claim 2, wherein the organic solvent is dichloromethane.
Claim 5
Dependent Claim
16 words
The method of claim 1, wherein the Lewis base salt is benzalkonium chloride or cetylpyridinium chloride.
Claim 6
Dependent Claim
13 words
The method of claim 4, wherein the Lewis acid salt is sodium carboxymethylcellulose.
Claim 7
Dependent Claim
29 words
The method of claim 1, wherein the Lewis acid salt is sodium carboxymethylcellulose, a sodium salt of polyacrylic acid, or a sodium salt of a polyoxyethylene cross-linked polyacrylic acid.
Claim 8
Dependent Claim
12 words
The method of claim 1, wherein the core material is a pharmaceutical.
References Cited (Backward Citations)
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Cited
US3959457A
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US3909441A
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US4003846A
Cited
US4324683A
Cited
JPS59128324A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-01-10 | 1992-07-11 | 1993-01-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-01-10 | 1996-07-11 | 1997-01-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-01-10 | 2000-07-11 | 2001-01-10 | $7700.00 | Window Closed / Lapsed |