US4898734A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polymer composite for controlled release or membrane formation
Assignee: Massachusetts Institute of Technology
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Filing: 1988-02-29
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Granted: 1990-02-06
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Expires: 2008-02-29
Abstract
Abstract The present invention is a method to produce novel composites based on microcapsules or microspheres embedded in contiuous polymeric matrices. Both non-bioerodible and erodible polymers can be used. Material can be incorporated into the microcapsules or microspheres for subsequent release. In one embodiment of the present invention, spheres are homogeneously dispersed in a polymer matrix and then forced to release their contents by exposure to temperature, light or ultrasound. Alternatively, polymers which degrade as a function of time or hydrolysis can be used for controlled releases. The polymer composites have completely different properties from either a continuous polymer matrix or microcapsules or microspheres and are therefore useful for a wide variety of applications. When carbon tetrachloride is the incorporated material, the film is useful as a flame retarding device. When foaming agents are used, especially UV or heat sensitive materials, gas can be evolved inside each capsul The Government has rights in this invention pursuant to Grant Number 5-R01-GM26698 awarded by the Department of Health and Human Services.
Inventors
- 👤 Edith Mathiowitz
- 👤 Robert S. Langer
- 👤 Abraham Warshawsky
- 👤 Elazar Edelman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 06:22
CPC Classifications
A; A01; A01N; A01N25/00; A01N25/34; A61; A61K; A61K9/00; A61K9/14; A61K9/16; A61K9/1605; A61K9/1629; A61K9/1641; A61K9/1647; A61K9/20; A61K9/2072; A61K9/2077; A61K9/2081; A61K9/70; A61K9/7023; B; B01; B01J; B01J13/00; B01J13/02; B01J13/025
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
38 words
A method for making a composite polymeric device comprising: providing a compound to be released, incorporating the compound to be released into polymer spheres, mixing the polymer spheres into a liquified polymer matrix, and solidifying the polymer matrix.
Claim 2
Independent Claim
38 words
A method for making a composite polymeric device comprising: providing a compound to be released, incorporating the compound to be released into polymer spheres, mixing the polymer spheres into a liquified polymer matrix, and solidifying the polymer matrix.
Claim 3
Dependent Claim
47 words
The method of claim 1, wherein the polymer spheres are embedded within the liquified polymer matrix by dissolving the polymer matrix in an organic solvent in which the polymer spheres are not soluble, suspending the polymer spheres in the liquified polymer matrix solution, and removing the solvent.
Claim 4
Dependent Claim
23 words
The method of claim 2 wherein the liquified polymer matrix is dissolved in an amount of organic solvent which produces a viscous solution.
Claim 5
Dependent Claim
21 words
The method of claim 2 wherein the solvent is highly volatile and is rapidly removed by evaporation before the microspheres settle.
Claim 6
Dependent Claim
32 words
The method of claim 1, wherein the compound to be released is selected from the group consisting of solvents, lubricants, flame retardants, preservatives, antioxidants, bioactive compounds, insecticides, herbicides, fertilizers, and foaming agents.
Claim 7
Dependent Claim
33 words
The method of claim 1, wherein the polymers are selected from the group consisting of polystyrene, polyethylene acetate, polyethylenevinyl acetate, polyurethane, polyamide, polyacrylamide, polymethacrylate, polylactic acid, polyglycolic acid, polyanhydrides, polyorthoester, and derivatives thereof.
Claim 8
Dependent Claim
31 words
The method of claim 1, wherein the compound to be released is a drug, at least one polymers is biodegradable, and the drug is released by erosion of the erodible polymer.
Claim 9
Independent Claim
33 words
A method for forming a porous membrane comprising providing polymer spheres, mixing the polymer spheres within a liquified polymeric matrix, and rupturing the polymer spheres to leave pores in the solidified polymeric matrix.
Claim 10
Independent Claim
33 words
A method for forming a porous membrane comprising providing polymer spheres, mixing the polymer spheres within a liquified polymeric matrix, and rupturing the polymer spheres to leave pores in the solidified polymeric matrix.
Claim 11
Dependent Claim
37 words
The method of claim 8 further comprising encapsulating a gas forming compound within the polymer spheres and releasing the gas when the polymer spheres are ruptured into the continuous polymeric matrix to produce a porous polymeric structure.
Claim 12
Dependent Claim
17 words
The method of claim 9 further comprising using the porous structure at a site for cell growth.
Claim 13
Dependent Claim
17 words
The method of claim 10 further comprising using the porous structure as a membrane of varying porosity.
Claim 14
Dependent Claim
20 words
The polymeric device of claim 3 wherein said polymer matrix can be applied directly to the skin of a patient.
Claim 15
Dependent Claim
47 words
The polymeric device of claim 9 wherein said polymer spheres are ruptured within said polymeric matrix by exposure to ultrasound, light, radiation, or temperature, said polymer spheres contain a bioactive compound, and the bioactive compound diffuses out of said polymeric matrix following rupture of said polymer spheres.
Claim 16
Dependent Claim
12 words
The method of claim 1, wherein the liquified polymer matrix is melted.
Claim 17
Dependent Claim
17 words
The method of claim 1, wherein the polymer matrix is liquified by heating and solidified by cooling.
Claim 18
Dependent Claim
17 words
The method of claim 1, wherein the polymer matrix is solidified by polymerizing monomers of the polymer.
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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) | 1993-02-05 | 1993-08-07 | 1994-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-05 | 1997-08-07 | 1998-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-05 | 2001-08-07 | 2002-02-06 | $7700.00 | Window Closed / Lapsed |