Lyophilized foams of end block-containing absorbable polymers

Patent metadata

Field	Value
Publication number	US-11118025-B2
Application number	US-201815864207-A
Country	US
Kind code	B2
Filing date	Jan 8, 2018
Priority date	Jun 2, 2015
Publication date	Sep 14, 2021
Grant date	Sep 14, 2021

Abstract

Novel absorbable foams, lyophilizing solutions, and lyophilizing and annealing processes are disclosed. The foams are made from copolymers of glycolide and epsilon-caprolactone. The foams are useful in or as implantable medical devices.

First claim

We claim:

1. A method of making an absorbable foam by a lyophilization process, comprising the steps of:
a) providing an absorbable polymer comprising a semicrystalline, absorbable, segmented block copolymer having a random center block segment of repeating units of polymerized glycolide and polymerized epsilon-caprolactone, and an end block segment that comprises predominantly polymerized glycolide, wherein the mole ratio of polymerized glycolide to polymerized epsilon-caprolactone of the entire segmented copolymer is about 55:45 to about 65:35, and having a mole ratio of polymerized glycolide to polymerized epsilon-caprolactone in the random center block segment between about 45:55 to about 52:48;
b) dissolving a sufficient quantity of the copolymer in a suitable solvent to form a lyophilizing solution;
c) pouring at least a part of the solution at a sufficiently effective temperature to prevent premature gel formation into a suitable mold;
d) freezing the solution at a fast enough rate to prevent premature gel formation in order to facilitate solvent removal in a subsequent lyophilization process; and,
e) subjecting the frozen solution in the mold to a lyophilizing process, wherein the pressure is lowered and heat is applied to sublimate the solvent and form an absorbable foam.

2. The method of claim 1 , wherein the copolymer has an inherent viscosity between about 0.5 dL/g and about 2.5 dl/g, as measured in a 0.1 g/dl solution of HFIP at 25° C.

3. The method of claim 1 , wherein the solvent is selected from the group consisting of 1,4-dioxane, a mixture of at least 90 weight percent 1,4-dioxane and no more than 10 weight percent water, and a mixture of at least 90 weight percent 1,4-dioxane and no more than 10 weight percent of an organic alcohol having a molecular weight of less than 1,500.

4. The method of claim 1 wherein the solid content of the lyophilizing solution is between about 3 and about 20 weight percent.

5. The method of claim 1 wherein the weight percentage of the dissolved copolymer in the lyophilizing solution formed by step b) is between about 5 and about 15 weight percent.

6. The method of claim 1 wherein the lyophilizing solution is poured at a temperature above 50° C. into the suitable mold.

7. The method of claim 1 , wherein the rate of freezing is equal to or faster than −5° C. per minute.

8. The method of claim 1 wherein the rate of freezing is equal to or faster than −10° C. per minute.

9. The method of claim 1 , wherein the absorbable polymer foam has a Degradation Coefficient at 2 mm height after 28 days of incubation in a buffer of pH 7.27 at 37° C. under continuous compression not greater than 0.065, wherein the degradation coefficient is determined from plots of compressive force over time, with the coefficient expressed as the decay coefficient of the exponential fit of the curve.

Assignees

• Ethicon Inc

Inventors

• Donners Jackie
• Wisnudel Marc
• Timmer Mark

Classifications

• A61L31/06 Primary

  obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds {(A61L31/041 takes precedence)} · CPC title

• A61L27/58

  Materials at least partially resorbable by the body · CPC title

• C08J2201/0482

  the liquid phase being organic · CPC title

• A61L27/56

  Porous materials, {e.g. foams or sponges} · CPC title

• C08J2300/16

  Biodegradable polymers · CPC title