# US 7,745,532 B2 · Systems and methods for controlling and forming polymer gels > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,745,532 B2 - Document ID: US7745532B2 - Status: Granted - Kind: B2 - Application number: 10/631,491 - Filed: 2003-07-31 - Published: 2004-05-13 - Granted: 2010-06-29 - Earliest claimed: 2002-08-02 - Assignees: Cambridge Polymer Group, Inc. - Inventors: Jeffrey W. Ruberti; Gavin J. C. Braithwaite - Web page: https://patentgrep.com/patent/US7745532B2 ## CPC - C08J 3/09: in organic liquids - A61K 9/0024: {Solid, semi-solid or solidifying implants, which are implanted or injected in body tissue (compositions for intravenous administration, normal injectable solutions or dispersions for, e.g. subcutaneous administration A61K9/0019; brain implants A61K9/0085; (coated) prostheses, catheters or stents A61L)} - C08J 2329/04: Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) - A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D) ## Abstract The preferred embodiments of the present invention provide polymer compositions and methods for controlling a property of a resultant gel. A preferred method includes dissolving a vinyl polymer in a first solvent to form a solution; and contacting the vinyl polymer solution in a suitable volume of at least one immersion solvent comprising a second solvent to cause gelation. In preferred embodiments, the invention provides poly(vinyl alcohol) compositions and methods that produce physically crosslinked hydrogels that have tunable physical properties. Also provided are articles of manufacture such as prosthetic intervertebral disks and contact lenses. ## Claims ### Claim 1 A method of controlling properties and forming a physically crosslinked, biocompatible hydrogel for a medical implant, wherein the method comprises the steps of: (a) dissolving vinyl polymer molecules in a first solution to form a vinyl polymer solution, wherein the first solution has a Flory interaction parameter (chi value) that is not sufficient for gelation; (b) contacting the vinyl polymer solution with a second solution in a controlled manner, wherein after the contacting the combination of both solutions has a Flory interaction parameter (chi value) that is sufficient for gelation in order to form a physically crosslinked, biocompatible hydrogel without chemical crosslinkers, irradiation or thermal cycling; and (c) providing the physically crosslinked, biocompatible hydrogel formed in step (b) for the medical implant, wherein the medical implant is a load bearing or non-load bearing material for replacement, repair or enhancement of tissue. ### Claim 2 (depends on 1) The method according to claim 1, wherein the first solution comprises one or more selected from the group consisting of deionized water and dimethylsulfoxide. ### Claim 3 (depends on 1) The method according to claim 1, wherein the biocompatible polymer hydrogel is anisotropic in one or more properties. ### Claim 4 (depends on 1) The method of claim 1, wherein the vinyl polymer solution comprises about 1.0 to about 50.0 weight percent polyvinyl alcohol. ### Claim 5 (depends on 1) The method of claim 1, wherein after the contacting the Flory interaction parameter is 0.25 to 1.0. ### Claim 6 (depends on 1) The method of claim 1, wherein the vinyl polymer solution contains one or more non-gelling components. ### Claim 7 (depends on 1) The method of claim 1, wherein the vinyl polymer solution includes hyaluronic acid. ### Claim 8 (depends on 1) The method of claim 1, wherein the vinyl polymer solution includes polyacrylic acid. ### Claim 9 (depends on 1) The method of claim 1, wherein the vinyl polymer solution includes a therapeutic agent. ### Claim 10 (depends on 1) The method of claim 1, wherein the vinyl polymer solution is placed in a dialysis chamber having at least two sides to permit introduction of a solution having a higher Flory interaction parameter than the vinyl polymer solution, wherein each side is a dialysis membrane that controls the rate of introduction of the solution having a higher Flory interaction parameter. ### Claim 11 (depends on 10) The method of claim 10, wherein the vinyl polymer solution is separated by the membranes from at least two different solvents. ### Claim 12 (depends on 10) The method of claim 10, wherein the vinyl polymer solution is separated by the membranes from a second solvent and a third solvent. ### Claim 13 (depends on 1) The method according to claim 1, wherein the implant is selected from the group consisting of a hip implant, spine implant, knee implant, elbow implant, shoulder implant, wrist implant, hand implant, ankle implant, foot implant, jaw implant, breast implant and artificial cartilage. ### Claim 14 A method of controlling properties and forming a physically crosslinked, biocompatible hydrogel for a medical device, wherein the method comprises the steps of: (a) dissolving vinyl polymer molecules in a first solution to form a vinyl polymer solution, wherein the first solution has a Flory interaction parameter (chi value) that is not sufficient for gelation; (b) contacting the vinyl polymer solution with a second solution in a controlled manner, wherein after the contacting the combination of both solutions has a Flory interaction parameter (chi value) that is sufficient for gelation in order to form a physically crosslinked, biocompatible hydrogel without chemical crosslinkers, irradiation or thermal cycling; and (c) providing the physically crosslinked, biocompatible hydrogel formed in step (b) for the medical device, wherein the medical device is for humans or animals. ### Claim 15 (depends on 14) The method according to claim 14, wherein the first solution comprises one or more selected from the group consisting of deionized water and dimethylsulfoxide. ### Claim 16 (depends on 14) The method according to claim 14, wherein the biocompatible polymer hydrogel is anisotropic in one or more properties. ### Claim 17 (depends on 14) The method of claim 14, wherein the vinyl polymer solution comprises about 1.0 to about 50.0 weight percent polyvinyl alcohol. ### Claim 18 (depends on 14) The method of claim 14, wherein after the contacting the Flory interaction parameter is 0.25 to 1.0. ### Claim 19 (depends on 14) The method of claim 14, wherein the vinyl polymer solution contains one or more non-gelling components. ### Claim 20 (depends on 14) The method of claim 14, wherein the vinyl polymer solution includes hyaluronic acid. ### Claim 21 (depends on 14) The method of claim 14, wherein the vinyl polymer solution includes polyacrylic acid. ### Claim 22 (depends on 14) The method of claim 14, wherein the vinyl polymer solution includes a therapeutic agent. ### Claim 23 (depends on 14) The method of claim 14, wherein the vinyl polymer solution is placed in a dialysis chamber having at least two sides to permit introduction of a solution having a higher Flory interaction parameter than the vinyl polymer solution, wherein each side is a dialysis membrane that controls the rate of introduction of the solution having a higher Flory interaction parameter. ### Claim 24 (depends on 23) The method of claim 23, wherein the vinyl polymer solution is separated by the membranes from at least two different solvents. ### Claim 25 (depends on 23) The method of claim 23, wherein the vinyl polymer solution is separated by the membranes from a second solvent and a third solvent. ### Claim 26 (depends on 14) The method according to claim 14, wherein the medical device is selected from the group consisting of active bandages, trans-epithelial drug delivery devices, drug release structure, filters, microfluidic devices, sponges, anti-adhesion materials, artificial vitreous humor, contact lens, and stents. ### Claim 27 (depends on 1) The method according to claim 1, wherein the implant is selected from the group consisting of a drug delivery device, drug release structure, filter, microfluidic device, sponge, anti-adhesion material, artificial vitreous humor, contact lens, breast implant, stent and artificial cartilage.