Patent US4911952A successfully refreshed from Google Patents.
US4911952A
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US
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Encapsulation by entrapment within matrix of unmodified starch
Assignee: United States Department of Agriculture
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Filing: 1987-07-10
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Granted: 1990-03-27
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Expires: 2007-07-10
Abstract
Abstract Chemical biological agents to be encapsulated are blended into an aqueous dispersion of an unmodified starch comprising about 5% to about 25% by weight amylose. The dispersion, having an initial starch solids content of about 20% by weight, is characterized by completely disrupted starch granules and completely disassociated amylose molecules that are not significantly depolymerized. Subsequent drying is accomplished by reassociation of the amylose molecules which converts the dispersion into a protective matrix and binds the agents within the interstices of the reassociating starch chains. Rate of release of agents to the environment can be altered by varying the proportion of amylose in the starch. Encapsulation of biologically active compositions provides protection against degradative environmental conditions, improves safety in handling, and slows the release of such compounds to the surrounding medium.
Inventors
- 👤 William M. Doane
- 👤 Sukumar Maiti
- 👤 Robert E. Wing
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:26
CPC Classifications
C; C08; C08B; C08B30/00; C08B30/12; A; A01; A01N; A01N25/00; A01N25/08; A01N25/10; A61; A61K; A61K47/00; A61K47/30; A61K47/36; A61K9/00; A61K9/14; A61K9/16; A61K9/1605; A61K9/1629; A61K9/1652; C08L; C08L3/00; C08L3/12; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2989
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
183 words
A method for the encapsulation of a biologically active chemical agent comprising the steps: a. providing at elevated temperatures a dispersion consisting essentially of an unmodified, amylose-containing starch and water having an initial solids content of at least about 20% by weight, wherein the amylose comprises from about 5% to about 25% of said starch on a dry weight basis, and wherein the granules of starch are completely disrupted and the amylose molecules of the starch are substantially completely disassociated from one another without significant depolymerization; b. blending said agent into said dispersion to form a mixture of the starch dispersion and the agent, wherein the relative amount of said solids with respect to the agent is sufficient to entrap the agent within a matrix of the starch; and c. treating the mixture consisting essentially of said starch, water and agent under dehydrating conditions at a temperature within the range of about 30°-130° C. whereby the amylose components will reassociate with one another and thereby transform said mixture into a continuous insolubilized matrix having entrapped therein uniformly dispersed, discontinuous domains of the agent.
Claim 2
Independent Claim
183 words
A method for the encapsulation of a biologically active chemical agent comprising the steps: a. providing at elevated temperatures a dispersion consisting essentially of an unmodified, amylose-containing starch and water having an initial solids content of at least about 20% by weight, wherein the amylose comprises from about 5% to about 25% of said starch on a dry weight basis, and wherein the granules of starch are completely disrupted and the amylose molecules of the starch are substantially completely disassociated from one another without significant depolymerization; b. blending said agent into said dispersion to form a mixture of the starch dispersion and the agent, wherein the relative amount of said solids with respect to the agent is sufficient to entrap the agent within a matrix of the starch; and c. treating the mixture consisting essentially of said starch, water and agent under dehydrating conditions at a temperature within the range of about 30°-130° C. whereby the amylose components will reassociate with one another and thereby transform said mixture into a continuous insolubilized matrix having entrapped therein uniformly dispersed, discontinuous domains of the agent.
Claim 3
Dependent Claim
46 words
The method of claim 1 wherein said starch is selected from the group consisting of pearl corn starch, corn fluor, wheat starch, wheat flour, potato starch, potato flour, mixtures thereof, and mixtures thereof with waxy starch, high amylose starch, or the amylose fraction of a starch.
Claim 4
Dependent Claim
22 words
The method of claim 1 wherein the initial solids content of the dispersion is in the range of about 20-40% by weight.
Claim 5
Dependent Claim
15 words
The method of claim 1 wherein said starch dispersion is prepared by steam jet cooking.
Claim 6
Dependent Claim
17 words
The method of claim 1 wherein the elevated temperature is in the range of about 120°-135° C.
Claim 7
Dependent Claim
18 words
The method of claim 1 and further comprising the step of drying the mixture into a friable mass.
Claim 8
Dependent Claim
29 words
The method of claim 1 and further comprising the steps of drying the mixture into a friable mass, particularizing the friable mass into discrete particles, and recovering said particles.
Claim 9
Dependent Claim
40 words
The method as described in claim 1 wherein the biologically active chemical agent is a herbicide, insecticide, fungicide, nematocide, bactericide, rodenticide, molluscicide, acaricide, larvacide, fumigant, animal repellant, plant growth regulator, fertilizer, pheromone, flavor composition, odor composition, vitamin, mineral, or medicament.
Claim 10
Independent Claim
183 words
A method for the encapsulation of a biologically active chemical agent comprising the steps: a. providing at elevated temperatures a dispersion consisting essentially of an unmodified, amylose-containing starch and water having an initial solids content of at least about 20% by weight, wherein the amylose comprises from about 5% to about 25% of said starch on a dry weight basis, and wherein the granules of starch are completely disrupted and the amylose molecules of the starch are substantially completely disassociated from one another without significant depolymerization; b. blending said agent into said dispersion to form a mixture of the starch dispersion and the agent, wherein the relative amount of said solids with respect to the agent is sufficient to entrap the agent within a matrix of the starch; and c. treating the mixture consisting essentially of said starch, water and agent under dehydrating conditions whereby the amylose components will reassociate with one another and thereby transform said mixture at a solids content in the range of about 55-65% into a continuous insolubilized matrix having entrapped therein uniformly dispersed, discontinuous domains of the agent.
Claim 11
Independent Claim
183 words
A method for the encapsulation of a biologically active chemical agent comprising the steps: a. providing at elevated temperatures a dispersion consisting essentially of an unmodified, amylose-containing starch and water having an initial solids content of at least about 20% by weight, wherein the amylose comprises from about 5% to about 25% of said starch on a dry weight basis, and wherein the granules of starch are completely disrupted and the amylose molecules of the starch are substantially completely disassociated from one another without significant depolymerization; b. blending said agent into said dispersion to form a mixture of the starch dispersion and the agent, wherein the relative amount of said solids with respect to the agent is sufficient to entrap the agent within a matrix of the starch; and c. treating the mixture consisting essentially of said starch, water and agent under dehydrating conditions whereby the amylose components will reassociate with one another and thereby transform said mixture at a solids content in the range of about 55-65% into a continuous insolubilized matrix having entrapped therein uniformly dispersed, discontinuous domains of the agent.
Claim 12
Dependent Claim
36 words
A method as described in claim 9 wherein the initial solids content of the dispersion is in the range of about 20-40% by weight and said elevated temperature is in the range of about 120°-135° C.
Claim 13
Independent Claim
225 words
A method for tailoring the release rate of a biologically active chemical agent encapsulated within a starch matrix, the method comprising: a. selecting an unmodified starch or mixture of unmodified starches having a ratio of amylose to amylopectin corresponding to a predetermined ratio of amylose and amylopectin needed to impart the desired release properties to said matrix wherein the amylose comprises from about 5% to about 25% of said starch or mixture of starches on a dry weight basis; b. dispersing said starch or mixture of starches at elevated temperatures in water at an initial solids content of at least about 20% by weight, wherein the granules of starch are completely disrupted and the amylose molecules of the starch are substantially completely disassociated from one another without significant depolymerization; c. blending said agent into said dispersion to form a mixture of the starch dispersion and the agent, wherein the relative amount of said solids with respect to the agent is sufficient to entrap the agent within a matrix of the starch; and d. dehydrating the mixture consisting essentially of said starch, water and agent under conditions at a temperature within the range of about 30°-130° C. whereby the amylose components will reassociate with one another and thereby transform said mixture into a continuous insolubilized matrix having entrapped therein uniformly dispersed, discontinuous domains of the agent.
Claim 14
Independent Claim
225 words
A method for tailoring the release rate of a biologically active chemical agent encapsulated within a starch matrix, the method comprising: a. selecting an unmodified starch or mixture of unmodified starches having a ratio of amylose to amylopectin corresponding to a predetermined ratio of amylose and amylopectin needed to impart the desired release properties to said matrix wherein the amylose comprises from about 5% to about 25% of said starch or mixture of starches on a dry weight basis; b. dispersing said starch or mixture of starches at elevated temperatures in water at an initial solids content of at least about 20% by weight, wherein the granules of starch are completely disrupted and the amylose molecules of the starch are substantially completely disassociated from one another without significant depolymerization; c. blending said agent into said dispersion to form a mixture of the starch dispersion and the agent, wherein the relative amount of said solids with respect to the agent is sufficient to entrap the agent within a matrix of the starch; and d. dehydrating the mixture consisting essentially of said starch, water and agent under conditions at a temperature within the range of about 30°-130° C. whereby the amylose components will reassociate with one another and thereby transform said mixture into a continuous insolubilized matrix having entrapped therein uniformly dispersed, discontinuous domains of the agent.
Claim 15
Dependent Claim
46 words
The method of claim 11 wherein said starch is selected from the group consisting of pearl corn starch, corn flour, wheat starch, wheat flour, potato starch, potato flour, mixtures thereof, and mixtures thereof with waxy starch, high amylose starch, or the amylose fraction of a starch.
Claim 16
Dependent Claim
22 words
The method of claim 11 wherein the initial solids content of the dispersion is in the range of about 20-40% by weight.
Claim 17
Dependent Claim
15 words
The method of claim 11 wherein said starch dispersion is prepared by steam jet cooking.
Claim 18
Dependent Claim
17 words
The method of claim 11 wherein the elevated temperature is in the range of about 120°-135° C.
Claim 19
Dependent Claim
18 words
The method of claim 11 and further comprising the steps of drying the mixture into a friable mass.
Claim 20
Dependent Claim
29 words
The method of claim 11 and further comprising the steps of drying the mixture into a friable mass, particularizing the friable mass into discrete particles, and recovering said particles.
Claim 21
Dependent Claim
39 words
The method as described in claim 11 wherein the biologically active chemical is a herbicide, insecticide, fungicide, nematocide, bactericide, rodenticide, molluscicide, acaricide, larvacide, fumigant, animal repellant, plant growth regulator, fertilizer, pheromone, flavor composition, odor composition, vitamin, mineral, or medicament.
Claim 22
Independent Claim
225 words
A method for tailoring the release rate of a biologically active chemical agent encapsulated within a starch matrix, the method comprising: a. selecting an unmodified starch or mixture of unmodified starches having a ratio of amylose to amylopectin corresponding to a predetermined ratio of amylose and amylopectin needed to impart the desired release properties to said matrix wherein the amylose comprises from about 5% to about 25% of said starch or mixture of starches on a dry weight basis; b. dispersing said starch or mixture of starches at elevated temperatures in water at an initial solids content of at least about 20% by weight, wherein the granules of starch are completely disrupted and the amylose molecules of the starch are substantially completely disassociated from one another without significant depolymerization; c. blending said agent into said dispersion to form a mixture of the starch dispersion and the agent, wherein the relative amount of said solids with respect to the agent is sufficient to entrap the agent within a matrix of the starch; and d. dehydrating the mixture consisting essentially of said starch, water and agent under conditions whereby the amylose components will reassociate with one another and thereby transform said mixture at a solids content in the range of about 55-65% into a continuous insolubilized matrix having entrapped therein uniformly dispersed, discontinuous domains of the agent.
Claim 23
Independent Claim
225 words
A method for tailoring the release rate of a biologically active chemical agent encapsulated within a starch matrix, the method comprising: a. selecting an unmodified starch or mixture of unmodified starches having a ratio of amylose to amylopectin corresponding to a predetermined ratio of amylose and amylopectin needed to impart the desired release properties to said matrix wherein the amylose comprises from about 5% to about 25% of said starch or mixture of starches on a dry weight basis; b. dispersing said starch or mixture of starches at elevated temperatures in water at an initial solids content of at least about 20% by weight, wherein the granules of starch are completely disrupted and the amylose molecules of the starch are substantially completely disassociated from one another without significant depolymerization; c. blending said agent into said dispersion to form a mixture of the starch dispersion and the agent, wherein the relative amount of said solids with respect to the agent is sufficient to entrap the agent within a matrix of the starch; and d. dehydrating the mixture consisting essentially of said starch, water and agent under conditions whereby the amylose components will reassociate with one another and thereby transform said mixture at a solids content in the range of about 55-65% into a continuous insolubilized matrix having entrapped therein uniformly dispersed, discontinuous domains of the agent.
Claim 24
Dependent Claim
36 words
A method as described in claim 19 wherein the initial solids content of the dispersion is in the range of about 20-40% by weight and said elevated temperature is in the range of about 120°-135° C.
Claim 25
Dependent Claim
19 words
A product produced by the method of claims 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.
Claim 26
Dependent Claim
19 words
A product produced by the method of claims 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20.
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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) | 1993-03-26 | 1993-09-25 | 1994-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-26 | 1997-09-25 | 1998-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-26 | 2001-09-25 | 2002-03-27 | $7700.00 | Window Closed / Lapsed |