US5041292A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Biodegradable hydrogel matrices for the controlled release of pharmacologically active agents
Assignee: Actavis Laboratories UT Inc
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Filing: 1990-02-01
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Granted: 1991-08-20
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Expires: 2010-02-01
Abstract
Abstract A biodegradable hydrogel matrix is provided, useful for the controlled release of pharmacologically active agents. The matrix is formed by cross-linking a proteinaceous component and a polysaccharide or mucopolysaccharide, and then loading a selected drug therein. By varying temperature, ionic strength, and the composition of the hydrogel matrix, one can control degradation kinetics, the degree of uptake of a particular pharmacologically active agent, and the overall times release profile.
Inventors
- 👤 Jan Feijen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:29
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/20; A61K9/2004; A61K9/2022; A61K9/2063; A61K9/14; A61K9/16; A61K9/1605; A61K9/1629; A61K9/1652; A61K9/1658; A61K9/205
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
96 words
A method of preparing microspheres useful in the controlled release of drugs, comprising: (a) preparing an aqueous solution of a selected protein and a polysaccharide, wherein the weight ratio of polysaccharide to protein in the solution is in the range of about 10:90 to 90:10; (b) admixing the protein solution with oil to provide an emulsion, wherein the volume ratio of oil to protein is in the range of about 1:1 to 500:1; (c) introducing a cross-linking agent into the emulsion so as to cross-link the protein and polysaccharide; and (d) isolating the microspheres so formed.
Claim 2
Independent Claim
96 words
A method of preparing microspheres useful in the controlled release of drugs, comprising: (a) preparing an aqueous solution of a selected protein and a polysaccharide, wherein the weight ratio of polysaccharide to protein in the solution is in the range of about 10:90 to 90:10; (b) admixing the protein solution with oil to provide an emulsion, wherein the volume ratio of oil to protein is in the range of about 1:1 to 500:1; (c) introducing a cross-linking agent into the emulsion so as to cross-link the protein and polysaccharide; and (d) isolating the microspheres so formed.
Claim 3
Independent Claim
96 words
A method of preparing microspheres useful in the controlled release of drugs, comprising: (a) preparing an aqueous solution of a selected protein and a polysaccharide, wherein the weight ratio of polysaccharide to protein in the solution is in the range of about 10:90 to 90:10; (b) introducing a cross-linking agent into the solution so as to cross-link the protein and polysaccharide, and to provide a cross-linked mixture; (c) admixing the cross-linked mixture with oil to provide an emulsion, wherein the volume ratio of oil to protein is in the range of about 1:1 to 500:1; and
Claim 4
Independent Claim
96 words
A method of preparing microspheres useful in the controlled release of drugs, comprising: (a) preparing an aqueous solution of a selected protein and a polysaccharide, wherein the weight ratio of polysaccharide to protein in the solution is in the range of about 10:90 to 90:10; (b) introducing a cross-linking agent into the solution so as to cross-link the protein and polysaccharide, and to provide a cross-linked mixture; (c) admixing the cross-linked mixture with oil to provide an emulsion, wherein the volume ratio of oil to protein is in the range of about 1:1 to 500:1; and
Claim 5
Independent Claim
97 words
A method of preparing microspheres useful in the controlled release of drugs, comprising: preparing an aqueous solution of a selected protein and a polysaccharide, wherein the weight ratio of polysaccharide to protein in the solution is in the range of about 10:90 to 90:10; (b) admixing the aqueous solution with oil to provide an emulsion, wherein the volume ratio of oil to protein is in the range of about 1:1 to 500:1; (c) isolating the microspheres so formed; and (d) heating the microspheres to a temperature in the range of about 100° C. to about 170° C.
Claim 6
Independent Claim
97 words
A method of preparing microspheres useful in the controlled release of drugs, comprising: preparing an aqueous solution of a selected protein and a polysaccharide, wherein the weight ratio of polysaccharide to protein in the solution is in the range of about 10:90 to 90:10; (b) admixing the aqueous solution with oil to provide an emulsion, wherein the volume ratio of oil to protein is in the range of about 1:1 to 500:1; (c) isolating the microspheres so formed; and (d) heating the microspheres to a temperature in the range of about 100° C. to about 170° C.
Claim 7
Independent Claim
33 words
The method of any one of claims 1, 2 or 3, further comprising loading an effective amount of a drug into the microspheres by immersing the microspheres in a solution of the drug.
Claim 8
Dependent Claim
24 words
The method of claim 4 wherein the drug is selected from the group consisting of proteins, enzymes, mucopolysaccharides, peptides, hormones, antibodies and cytostatic agents.
Claim 9
Independent Claim
32 words
The method of any one of claims 1, 2 or 4, wherein the polysaccharide is selected from the group consisting of heparin, heparin fragments, heparan, heparan sulfate, chondroitin sulfate, and mixtures thereof.
Claim 10
Dependent Claim
22 words
The method of claim 6, wherein the polysaccharide is selected from the group consisting of heparin, heparin fragments, heparan and heparan sulfate.
Claim 11
Independent Claim
32 words
The method of any one of claims 1, 2 or 3, wherein the protein is selected from the group consisting of albumin, casein, fibrinogen, γ-globulin, hemoglobin, ferritin, elastin and synthetic α-amino peptides.
Claim 12
Dependent Claim
10 words
The method of claim 8 wherein the protein is albumin.
Claim 13
Independent Claim
18 words
The method of either of claims 1 or 2, wherein the cross-linking agent is an amide bond-forming agent.
Claim 14
Dependent Claim
13 words
The method of claim 10, wherein the amide-bond forming agent is a carbodiimide.
Claim 15
Dependent Claim
10 words
The method of claim 11, wherein the carbodiimide is N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide.
Claim 16
Dependent Claim
8 words
Microspheres produced by the method of claim 1.
Claim 17
Dependent Claim
8 words
Microspheres produced by the method of claim 2.
Claim 18
Dependent Claim
8 words
Microspheres produced by the method of claim 3.
Claim 19
Dependent Claim
9 words
Drug-containing microspheres produced by the method of claim 4.
Claim 20
Dependent Claim
9 words
Drug-containing microspheres produced by the method of claim 3.
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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) | 1994-08-19 | 1995-02-18 | 1995-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-08-19 | 1999-02-18 | 1999-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-08-19 | 2003-02-18 | 2003-08-20 | $7700.00 | Window Closed / Lapsed |