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US4439488A
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Encapsulation by entrapment within polyhydroxy polymer borates
Assignee: United States Department of Agriculture
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Filing: 1982-02-26
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Granted: 1984-03-27
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Expires: 2002-02-26
Abstract
Abstract Chemical biological agents to be encapsulated are dissolved or dispersed in an aqueous paste of a gel-forming polyhydroxy polymer. Subsequent addition of boric acid or a boric acid derivative at an alkaline pH converts the paste into a gel, thereby entrapping the agents in a protective matrix. Encapsulation of biologically active compositions provides a shield against hostile environments, improves safety in handling, and slows the release of such compounds to the surrounding medium. Highly volatile liquids are protected against losses by evaporation. Encapsulation also provides protection against decomposition from exposure to ultraviolet light.
Inventors
- 👤 Donald Trimnell
- 👤 Baruch S. Shasha
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:05
CPC Classifications
B; B01; B01J; B01J13/00; B01J13/02; B01J13/06; A; A01; A01N; A01N25/00; A01N25/26; A61; A61K; A61K9/00; A61K9/20; A61K9/28; A61K9/48; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2984; Y10T428/2985; Y10T428/2987; Y10T428/2989
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
126 words
A method of encapsulating a chemical biological agent comprising the steps of: a. preparing a solution or dispersion of a suitable chemical biological agent in a matrix-forming material comprising an aqueous paste of a gel-forming polyhydroxy polymer (PHP), wherein said paste has a solids concentration of said PHP of from about 10-40%, and wherein the relative amount of said PHP with respect to said biological agent is sufficient to entrap said agent within a matrix of said PHP; b. reacting from a single phase at an alkaline pH said PHP with boric acid or a boric acid derivative to form a continuous insolubilized matrix gel having entrapped therein uniformly dispersed, discontinuous domains of said agent; and c. recovering free-flowing particles of said entrapped chemical biological agent.
Claim 2
Independent Claim
126 words
A method of encapsulating a chemical biological agent comprising the steps of: a. preparing a solution or dispersion of a suitable chemical biological agent in a matrix-forming material comprising an aqueous paste of a gel-forming polyhydroxy polymer (PHP), wherein said paste has a solids concentration of said PHP of from about 10-40%, and wherein the relative amount of said PHP with respect to said biological agent is sufficient to entrap said agent within a matrix of said PHP; b. reacting from a single phase at an alkaline pH said PHP with boric acid or a boric acid derivative to form a continuous insolubilized matrix gel having entrapped therein uniformly dispersed, discontinuous domains of said agent; and c. recovering free-flowing particles of said entrapped chemical biological agent.
Claim 3
Dependent Claim
41 words
A method as described in claim 1 wherein the suitable chemical biological agent is a herbicide, insecticide, fungicide, nematocide, bactericide, rodenticide, molluscicide, acaricide, larvacide, fumigant, animal repellant, insect repellant, plant growth regulator, fertilizer, pheromone, sex lure, flavor composition, or odor composition.
Claim 4
Dependent Claim
26 words
A method as described in claim 1 wherein said gel-forming PHP is selected from the group consisting of starch, carboxymethyl cellulose, dextran, xylan, and polyvinyl alcohol.
Claim 5
Dependent Claim
14 words
A method as described in claim 1 wherein said gel-forming PHP is a starch.
Claim 6
Dependent Claim
20 words
A method as described in claim 4 wherein said starch is pregelatinized prior to preparation of said solution or dispersion.
Claim 7
Dependent Claim
19 words
A method as described in claim 4 wherein said pH is sufficiently alkaline to effect gelatinization of the starch.
Claim 8
Dependent Claim
23 words
A method as described in claim 1 wherein the pH of said solution or dispersion is in the range of 7.5 to 8.5.
Claim 9
Dependent Claim
27 words
A method as described in claim 7 wherein the pH is adjusted to within said range by the addition of ammonium hydroxide to said solution or dispersion.
Claim 10
Dependent Claim
58 words
A method as described in claim 1 wherein the recovering of free-flowing particles of said entrapped chemical biological agent comprises the steps of: (1) breaking the gel formed in step (b) into discrete particles; (2) admixing the particles with a powdery coating material whereby the particles become coated with said material; and (3) drying the discrete coated particles.
Claim 11
Dependent Claim
18 words
A method as described in claim 9 wherein said powdery coating material is a starch or starch-containing flour.
Claim 12
Dependent Claim
11 words
A composition of matter produced by the process of claim 1.
Claim 13
Dependent Claim
11 words
A composition of matter produced by the process of claim 2.
Claim 14
Dependent Claim
11 words
A composition of matter produced by the process of claim 3.
Claim 15
Dependent Claim
11 words
A composition of matter produced by the process of claim 4.
Claim 16
Dependent Claim
11 words
A composition of matter produced by the process of claim 10.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-03-27 | 1987-09-26 | 1988-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-27 | 1991-09-26 | 1992-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-27 | 1995-09-26 | 1996-03-27 | $7700.00 | Window Closed / Lapsed |