US5723508A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of fabricating emulsion freeze-dried scaffold bodies and resulting products
Assignee: Northwestern University
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Filing: 1996-01-25
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Granted: 1998-03-03
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Expires: 2016-01-25
Abstract
Abstract Scaffold bodies and methods for their fabrication are disclosed, and, more particularly, fabrication of scaffold bodies by freeze-drying emulsion of polymer solutions are disclosed.
Inventors
- 👤 Kevin E. Healy
- 👤 Kyumin Whang
- 👤 Carson H. Thomas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:51
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/26; A; A61; A61L; A61L27/00; A61L27/14; A61L27/18; C08J2367/00; C08J2367/04
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
145 words
A method of fabricating a porous molded scaffold body, comprising the steps of: (a) preparing an emulsion with a polar solvent dispersed in a non-polar solvent which is immiscible with said polar solvent, said non-polar solvent having dissolved therein from 5 to 20 parts by weight of a biocompatible polymer per each 100 parts total volume of both solvents, said polymer being insoluble in the dispersed polar solvent and forming a solid upon freeze-drying; (b) freezing said emulsion in a mold under conditions which convert both of said solvents to solids without breaking the emulsion or throwing the polymer out of solution, thereby obtaining a solid frozen body of molded shape; (c) subjecting the resulting molded frozen body to freeze-drying under conditions which convert the entire body to a porous solid; and (d) continuing the freeze-drying until said entire body is a porous open-celled body.
Claim 2
Independent Claim
145 words
A method of fabricating a porous molded scaffold body, comprising the steps of: (a) preparing an emulsion with a polar solvent dispersed in a non-polar solvent which is immiscible with said polar solvent, said non-polar solvent having dissolved therein from 5 to 20 parts by weight of a biocompatible polymer per each 100 parts total volume of both solvents, said polymer being insoluble in the dispersed polar solvent and forming a solid upon freeze-drying; (b) freezing said emulsion in a mold under conditions which convert both of said solvents to solids without breaking the emulsion or throwing the polymer out of solution, thereby obtaining a solid frozen body of molded shape; (c) subjecting the resulting molded frozen body to freeze-drying under conditions which convert the entire body to a porous solid; and (d) continuing the freeze-drying until said entire body is a porous open-celled body.
Claim 3
Dependent Claim
31 words
The method of claim 1 in which the polar solvent is water, the non-polar solvent is methylene chloride, and the polymer is selected from polylactic acid, polyglycolic acid, and copolymers thereof.
Claim 4
Dependent Claim
18 words
The method of claim 2 in which said polymer is a copolymer of polylactic acid and polyglycolic acid.
Claim 5
Independent Claim
185 words
A method of fabricating a porous molded scaffold body for delivery of a therapeutic agent, comprising the steps of: (a) preparing an emulsion with a polar solvent dispersed in a non-polar solvent which is immiscible with said polar solvent, said polar solvent containing a water-soluble therapeutic agent, the non-polar solvent having dissolved therein from 5 to 20 parts by weight of a biocompatible polymer per each 100 parts by volume of the total solvents, said polymer being insoluble in said polar solvent and forming a solid on removing the non-polar solvent; (b) introducing a portion of said emulsion into a mold in which it can be frozen; (c) freezing said emulsion in said mold under conditions which convert both of said solvents to solids without breaking the emulsion or throwing the polymer out of solution, thereby obtaining a solid frozen body of molded shape; (d) subjecting the resulted molded frozen body to freeze-drying under conditions which remove said solvents and convert the entire body to a porous solid; and (e) continuing the freeze-drying until said body is a porous open-celled body having a molded shape.
Claim 6
Independent Claim
185 words
A method of fabricating a porous molded scaffold body for delivery of a therapeutic agent, comprising the steps of: (a) preparing an emulsion with a polar solvent dispersed in a non-polar solvent which is immiscible with said polar solvent, said polar solvent containing a water-soluble therapeutic agent, the non-polar solvent having dissolved therein from 5 to 20 parts by weight of a biocompatible polymer per each 100 parts by volume of the total solvents, said polymer being insoluble in said polar solvent and forming a solid on removing the non-polar solvent; (b) introducing a portion of said emulsion into a mold in which it can be frozen; (c) freezing said emulsion in said mold under conditions which convert both of said solvents to solids without breaking the emulsion or throwing the polymer out of solution, thereby obtaining a solid frozen body of molded shape; (d) subjecting the resulted molded frozen body to freeze-drying under conditions which remove said solvents and convert the entire body to a porous solid; and (e) continuing the freeze-drying until said body is a porous open-celled body having a molded shape.
Claim 7
Dependent Claim
45 words
The method of claim 4 in which said non-polar solvent is selected from methylene chloride, carbon tetrachloride, chloroform, cyclohexane, toluene, and mixtures thereof, said polar solvent is selected from water, acetic acid, methanol, ethanol, and mixtures thereof, and said therapeutic agent is a water-soluble protein.
Claim 8
Dependent Claim
39 words
The method of claim 4 in which the polar solvent is water, the non-polar solvent is methylene chloride, the polymer is a co-polymer of polylactic acid and polyglycolic acid, and the therapeutic agent is a water-soluble bone morphogenetic agent.
Claim 9
Independent Claim
205 words
A method of fabricating a porous molded scaffold body, comprising the steps of: (a) preparing an emulsion with an aqueous phase dispersed in non-polar volatile liquid solvent phase which is immiscible with water, said aqueous phase having a volume of from 20 to 60 parts per 100 total parts by volume of both the aqueous phase and the non-polar solvent phase, said non-polar solvent phase having dissolved therein from 5 to 20 parts by weight of a bioabsorbable polymer per each 100 total parts by volume of both phases; (b) introducing a portion of said emulsion into a mold in which it can be frozen; (c) freezing said emulsion in said mold under conditions which convert both of said phases to solids without breaking the emulsion or throwing the polymer out of solution, thereby obtaining a solid frozen body of molded shape; (d) subjecting the resulted frozen body in said mold to freeze-drying under conditions which remove said solvents, the polymer converting to a solid condition as said non-polar solvent is removed; (e) continuing said freeze-drying until the polymer forms into a porous open-celled body having the shape of said mold; and (f) removing the porous body from the mold to obtain the scaffold body.
Claim 10
Independent Claim
205 words
A method of fabricating a porous molded scaffold body, comprising the steps of: (a) preparing an emulsion with an aqueous phase dispersed in non-polar volatile liquid solvent phase which is immiscible with water, said aqueous phase having a volume of from 20 to 60 parts per 100 total parts by volume of both the aqueous phase and the non-polar solvent phase, said non-polar solvent phase having dissolved therein from 5 to 20 parts by weight of a bioabsorbable polymer per each 100 total parts by volume of both phases; (b) introducing a portion of said emulsion into a mold in which it can be frozen; (c) freezing said emulsion in said mold under conditions which convert both of said phases to solids without breaking the emulsion or throwing the polymer out of solution, thereby obtaining a solid frozen body of molded shape; (d) subjecting the resulted frozen body in said mold to freeze-drying under conditions which remove said solvents, the polymer converting to a solid condition as said non-polar solvent is removed; (e) continuing said freeze-drying until the polymer forms into a porous open-celled body having the shape of said mold; and (f) removing the porous body from the mold to obtain the scaffold body.
Claim 11
Dependent Claim
25 words
The method of claim 7 in which the non-polar solvent is methylene chloride and the polymer is a copolymer of polylactic acid and polyglycolic acid.
Claim 12
Dependent Claim
20 words
The porous, molded scaffold bodies produced by the method of claims 1, 2, 3, 4, 5, 6, 7, or 8.
References Cited (Backward Citations)
US4818542A
Cited
US5100669A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-03-02 | 2001-09-01 | 2002-03-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-03-02 | 2005-09-01 | 2006-03-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-03-02 | 2009-09-01 | 2010-03-03 | $7700.00 | Window Closed / Lapsed |