Patents by Inventor Chandrashekhar P. Pathak
Chandrashekhar P. Pathak has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6410645Abstract: Gel-forming macromers including at least four polymeric blocks, at least two of which are hydrophobic and at least one of which is hydrophilic, and including a crosslinkable group are provided. The macromers can be covalently crosslinked to form a gel on a tissue surface in vivo. The gels formed from the macromers have a combination of properties including thermosensitivity and lipophilicity, and are useful in a variety of medical applications including drug delivery and tissue coating.Type: GrantFiled: November 9, 2000Date of Patent: June 25, 2002Assignee: Focal, Inc.Inventors: Chandrashekhar P. Pathak, Shikha P. Barman, C. Michael Philbrook, Amarpreet S. Sawhney, Arthur J. Coury, Luis Z. Avila, Mark T. Kieras
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Publication number: 20020058318Abstract: This invention provides novel methods for the formation of biocompatible membranes around biological materials using photopolymerization of water soluble molecules. The membranes can be used as a covering to encapsulate biological materials or biomedical devices, as a “glue” to cause more than one biological substance to adhere together, or as carriers for biologically active species.Type: ApplicationFiled: March 19, 2001Publication date: May 16, 2002Applicant: THE BOARD OF REGENTS, THE UNIVERSITY OF TEXAS SYSTEMInventors: Jeffrey A. Hubbell, Chandrashekhar P. Pathak, Amarpreet S. Sawhney, Neil P. Desai, Syed F.A. Hossainy
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Patent number: 6322593Abstract: A method for treating biological tissue is provided in which a cross-linked biological tissue containing free aldehyde groups is reacted with a suitable neutralization agent in order to chemically block the aldehyde groups from reactivity toward cellular proteins. Also provided is the cross-linked biological tissue so produced which is substantially free of reactive aldehyde groups and, as a result, exhibits reduced toxicity and improved biocompatibility.Type: GrantFiled: April 9, 1999Date of Patent: November 27, 2001Assignee: Sulzer Carbomedics Inc.Inventors: Chandrashekhar P. Pathak, Mark A. Moore, Richard E. Philips, Jr.
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Patent number: 6306922Abstract: Hydrogels of polymerized and crosslinked macromers comprising hydrophilic oligomers having biodegradable monomeric or oligomeric extensions, which biodegradable extensions are terminated on free ends with end cap monomers or oligomers capable of polymerization and cross linking are described. The hydrophilic core itself may be degradable, thus combining the core and extension functions. Macromers are polymerized using free radical initiators under the influence of long wavelength ultraviolet light, visible light excitation or thermal energy. Biodegradation occurs at the linkages within the extension oligomers and results in fragments which are non-toxic and easily removed from the body. Preferred applications for the hydrogels include prevention of adhesion formation after surgical procedures, controlled release of drugs and other bioactive species, temporary protection or separation of tissue surfaces, adhering of sealing tissues together, and preventing the attachment of cells to tissue surfaces.Type: GrantFiled: January 26, 2000Date of Patent: October 23, 2001Assignee: Boards of Regents, The University of Texas SystemInventors: Jeffrey A. Hubbell, Chandrashekhar P. Pathak, Amarpreet S. Sawhney, Neil P. Desai, Jennifer L. Hill
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Patent number: 6261544Abstract: A method for alleviating the symptoms of a cosmetic or dermatologic skin condition is described. An effective amount of a poly(hydroxy acid)/polymer conjugate in a pharmaceutically or cosmetically acceptable vehicle is provided. Topical compositions of the conjugates with another cosmetic or dermatological agent, and compounds of the conjugates having attached physiologically active functional groups, are also provided.Type: GrantFiled: February 15, 1999Date of Patent: July 17, 2001Assignee: Focal, Inc.Inventors: Arthur J. Coury, Luis Z. Avila, Chandrashekhar P. Pathak, Shikha P. Barman
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Patent number: 6258870Abstract: This invention provides novel methods for the formation of biocompatible membranes around biological materials using photopolymerization of water soluble molecules. The membranes can be used as a covering to encapsulate biological materials or biomedical devices, as a “glue” to cause more than one biological substance to adhere together, or as carriers for biologically active species. Several methods for forming these membranes are provided. Each of these methods utilizes a polymerization system containing water-soluble macromers, species which are at once polymers and macromolecules capable of further polymerization. The macromers are polymerized using a photoinitiator (such as a dye), optionally a cocatalyst, optionally an accelerator, and radiation in the form of visible or long wavelength UV light. The reaction occurs either by suspension polymerization or by interfacial polymerization.Type: GrantFiled: January 13, 1997Date of Patent: July 10, 2001Assignee: Board of Regents, The University of Texas SystemsInventors: Jeffrey A. Hubbell, Chandrashekhar P. Pathak, Amarpreet S. Sawhney, Neil P. Desai, Syed F. A. Hossainy
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Patent number: 6201065Abstract: Gel-forming macromers including at least four polymeric blocks, at least two of which are hydrophobic and at least one of which is hydrophilic, and including a crosslinkable group are provided. The macromers can be covalently crosslinked to form a gel on a tissue surface in vivo. The gels formed from the macromers have a combination of properties including thermosensitivity and lipophilicity, and are useful in a variety of medical applications including drug delivery and tissue coating.Type: GrantFiled: July 26, 1996Date of Patent: March 13, 2001Assignee: Focal, Inc.Inventors: Chandrashekhar P. Pathak, Shikha P. Barman, C. Michael Philbrook, Amarpreet S. Sawhney, Arthur J. Coury, Luis Z. Avila, Mark T. Kieras
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Patent number: 6177514Abstract: A method for cross-linking biological tissue is provided which uses as a cross-linking agent a low molecular weight, substantially monomeric polyfunctional aldehyde formed in situ or just prior to cross-linking. The polyfunctional aldehyde is essentially free of the undesirable heterogeneous polymeric species that result from polyfunctional aldehyde self-reactivity. Also provided is biological tissue that is cross-linked with a substantially monomeric glutaraldehyde.Type: GrantFiled: April 9, 1999Date of Patent: January 23, 2001Assignee: Sulzer Carbomedics Inc.Inventors: Chandrashekhar P. Pathak, Mark A. Moore, Richard E. Philips, Jr.
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Patent number: 6176871Abstract: A method and apparatus for molding polymeric structures in vivo is disclosed. The structures comprise polymers that may be heated to their molding temperature by absorption of visible or near-visible wavelengths of light. By providing a light source that produces radiation of the wavelength absorbed by the polymeric material, the material may be selectively heated and shaped in vivo without a corresponding heating of adjacent tissues or fluids to unacceptable levels. The apparatus comprises a catheter having a shaping element positioned near its distal end. An emitter provided with light from at least one optical fiber is positioned within the shaping element. The emitter serves to provide a moldable polymeric article positioned on the shaping element with a substantially uniform light field, thereby allowing the article to be heated and molded at a desired treatment site in a body lumen.Type: GrantFiled: October 14, 1998Date of Patent: January 23, 2001Assignee: Focal, Inc.Inventors: Chandrashekhar P. Pathak, Amarpreet S. Sawhney, Jeffrey A. Hubbell, Stephen J. Herman, Laurence A. Roth, Patrick K. Campbell, Kevin M. Berrigan, Peter K. Jarrett, Arthur J. Coury
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Patent number: 6060582Abstract: Hydrogels of polymerized and crosslinked macromers comprising hydrophilic oligomers having biodegradable monomeric or oligomeric extensions, which biodegradable extensions are terminated on free ends with end cap monomers or oligomers capable of polymerization and cross linking are described. The hydrophilic core itself may be degradable, thus combining the core and extension functions. Macromers are polymerized using free radical initiators under the influence of long wavelength ultraviolet light, visible light excitation or thermal energy. Biodegradation occurs at the linkages within the extension oligomers and results in fragments which are non-toxic and easily removed from the body. Preferred applications for the hydrogels include prevention of adhesion formation after surgical procedures, controlled release of drugs and other bioactive species, temporary protection or separation of tissue surfaces, adhering of sealing tissues together, and preventing the attachment of cells to tissue surfaces.Type: GrantFiled: August 4, 1998Date of Patent: May 9, 2000Assignee: The Board of Regents, The University of Texas SystemInventors: Jeffrey A. Hubbell, Chandrashekhar P. Pathak, Amarpreet S. Sawhney, Neil P. Desai, Jennifer L. Hill-West
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Patent number: 5986043Abstract: Hydrogels of polymerized and crosslinked macromers comprising hydrophilic oligomers having biodegradable monomeric or oligomeric extensions, which biodegradable extensions are terminated on free ends with end cap monomers or oligomers capable of polymerization and cross linking are described. The hydrophilic core itself may be degradable, thus combining the core and extension functions. Macromers are polymerized using free radical initiators under the influence of long wavelength ultraviolet light, visible light excitation or thermal energy. Biodegradation occurs at the linkages within the extension oligomers and results in fragments which are non-toxic and easily removed from the body. Preferred applications for the hydrogels include prevention of adhesion formation after surgical procedures, controlled release of drugs and other bioactive species, temporary protection or separation of tissue surfaces, adhering of sealing tissues together, and preventing the attachment of cells to tissue surfaces.Type: GrantFiled: August 20, 1996Date of Patent: November 16, 1999Assignee: Board of Regents, The University of Texas SystemInventors: Jeffrey A. Hubbell, Chandrashekhar P. Pathak, Amarpreet S. Sawhney, Neil P. Desai, Jennifer L. Hill-West
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Patent number: 5879688Abstract: A method for alleviating the symptoms of a cosmetic or dermatologic skin condition is described. An effective amount of a poly(hydroxy acid)/polymer conjugate in a pharmaceutically or cosmetically acceptable vehicle is provided. Topical compositions of the conjugates with another cosmetic or dermatological agent, and compounds of the conjugates having attached physiologically active functional groups, are also provided.Type: GrantFiled: October 30, 1996Date of Patent: March 9, 1999Assignee: Focal, Inc.Inventors: Arthur J. Coury, Luis Z. Avila, Chandrashekhar P. Pathak, Shikha P. Barman
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Patent number: 5858746Abstract: Water soluble macromers are modified by addition of free radical polymerizable groups, such as those containing a carbon-carbon double or triple bond, which can be polymerized under mild conditions to encapsulate tissues, cells, or biologically active materials. The polymeric materials are particularly useful as tissue adhesives, coatings for tissue lumens including blood vessels, coatings for cells such as islets of Langerhans, coatings, plugs, supports or substrates for contact with biological materials such as the body, and as drug delivery devices for biologically active molecules.Type: GrantFiled: January 25, 1995Date of Patent: January 12, 1999Assignee: Board of Regents, The University of Texas SystemInventors: Jeffrey A. Hubbell, Chandrashekhar P. Pathak, Amarpreet S. Sawhney, Neil P. Desai, Jennifer L. Hill, Syed F. A. Hossainy
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Patent number: 5849035Abstract: A method and apparatus for molding polymeric structures in vivo is disclosed. The structures comprise polymers that may be heated to their molding temperature by absorption of visible or near-visible wavelengths of light. By providing a light source that produces radiation of the wavelength absorbed by the polymeric material, the material may be selectively heated and shaped in vivo without a corresponding heating of adjacent tissues or fluids to unacceptable levels. The apparatus comprises a catheter having a shaping element positioned near its distal end. An emitter provided with light from at least one optical fiber is positioned within the shaping element. The emitter serves to provide a moldable polymeric article positioned on the shaping element with a substantially uniform light field, thereby allowing the article to be heated and molded at a desired treatment site in a body lumen.Type: GrantFiled: October 30, 1995Date of Patent: December 15, 1998Assignee: Focal, Inc.Inventors: Chandrashekhar P. Pathak, Amarpreet S. Sawhney, Jeffrey A. Hubbell, Stephen J. Herman, Laurence A. Roth, Patrick K. Campbell, Kevin M. Berrigan, Peter K. Jarrett, Arthur J. Coury
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Patent number: 5843743Abstract: Water soluble macromers are modified by addition of free radical polymerizable groups, such as those containing a carbon-carbon double or triple bond, which can be polymerized under mild conditions to encapsulate tissues, cells, or biologically active materials. The polymeric materials are particularly useful as tissue adhesives, coatings for tissue lumens including blood vessels, coatings for cells such as islets of Langerhans, coatings, plugs, supports or substrates for contact with biological materials such as the body, and as drug delivery devices for biologically active molecules.Type: GrantFiled: June 6, 1995Date of Patent: December 1, 1998Assignee: Board of Regents, The university of Texas SystemInventors: Jeffrey A. Hubbell, Chandrashekhar P. Pathak, Amarpreet S. Sawhney, Neil P. Desai, Jennifer L. Hill, Syed F. A. Hossainy
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Patent number: 5834274Abstract: Water soluble macromers are modified by addition of free radical polymerizable groups, such as those containing a carbon-carbon double or triple bond, which can be polymerized under mild conditions to encapsulate tissues, cells, or biologically active materials. The polymeric materials are particularly useful as tissue adhesives, coatings for tissue lumens including blood vessels, coatings for cells such as islets of Langerhans, coatings, plugs, supports or substrates for contact with biological materials such as the body, and as drug delivery devices for biologically active molecules.Type: GrantFiled: June 6, 1995Date of Patent: November 10, 1998Assignee: Board of Regents, The University of Texas SystemInventors: Jeffrey A. Hubbell, Chandrashekhar P. Pathak, Amarpreet S. Sawhney, Neil P. Desai, Jennifer L. Hill, Syed F. A. Hossainy
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Patent number: 5801033Abstract: This invention provides novel methods for the formation of biocompatible membranes around biological materials using photopolymerization of water soluble molecules. The membranes can be used as a covering to encapsulate biological materials or biomedical devices, as a "glue" to cause more than one biological substance to adhere together, or as carriers for biologically active species. Several methods for forming these membranes are provided. Each of these methods utilizes a polymerization system containing water-soluble macromers, species which are at once polymers and macromolecules capable of further polymerization. The macromers are polymerized using a photoinitiator (such as a dye), optionally a cocatalyst, optionally an accelerator, and radiation in the form of visible or long wavelength UV light. The reaction occurs either by suspension polymerization or by interfacial polymerization.Type: GrantFiled: June 7, 1995Date of Patent: September 1, 1998Assignee: The Board of Regents, The University of Texas SystemInventors: Jeffrey A. Hubbell, Chandrashekhar P. Pathak, Amarpreet S. Sawhney, Neil P. Desai, Syed F. A. Hossainy
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Patent number: 5741323Abstract: A method and apparatus for molding polymeric structures in vivo is disclosed. The structures comprise polymers that may be heated to their molding temperature by absorption of visible or near-visible wavelengths of light. By providing a light source that produces radiation of the wavelength absorbed by the polymeric material, the material may be selectively heated and shaped in vivo without a corresponding heating of adjacent tissues or fluids to unacceptable levels. The apparatus comprises a catheter having a shaping element positioned near its distal end. An emitter provided with light from at least one optical fiber is positioned within the shaping element. The emitter serves to provide a moldable polymeric article positioned on the shaping element with a substantially uniform light field, thereby allowing the article to be heated and molded at a desired treatment site in a body lumen.Type: GrantFiled: June 7, 1995Date of Patent: April 21, 1998Assignee: Focal, Inc.Inventors: Chandrashekhar P. Pathak, Amarpreet S. Sawhney, Jeffrey A. Hubbell, Stephen J. Herman, Laurence A. Roth, Patrick K. Campbell, Kevin M. Berrigan, Peter K. Jarrett, Arthur J. Coury
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Patent number: 5662712Abstract: A method and apparatus for molding polymeric structures in vivo is disclosed. The structures comprise polymers that may be heated to their molding temperature by absorption of visible or near-visible wavelengths of light. By providing a light source that produces radiation of the wavelength absorbed by the polymeric material, the material may be selectively heated and shaped in vivo without a corresponding heating of adjacent tissues or fluids to unacceptable levels. The apparatus comprises a catheter having a shaping element positioned near its distal end. An emitter provided with light from at least one optical fiber is positioned within the shaping element. The emitter serves to provide a moldable polymeric article positioned on the shaping element with a substantially uniform light field, thereby allowing the article to be heated and molded at a desired treatment site in a body lumen.Type: GrantFiled: June 7, 1995Date of Patent: September 2, 1997Assignee: Focal, Inc.Inventors: Chandrashekhar P. Pathak, Amarpreet S. Sawhney, Jeffrey A. Hubbell, Stephen J. Herman, Laurence A. Roth, Patrick K. Campbell, Kevin M. Berrigan, Peter K. Jarrett, Arthur J. Coury
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Patent number: 5626863Abstract: Hydrogels of polymerized and crosslinked macromers comprising hydrophilic oligomers having biodegradable monomeric or oligomeric extensions, which biodegradable extensions are terminated on free ends with end cap monomers or oligomers capable of polymerization and cross linking are described. The hydrophilic core itself may be degradable, thus combining the core and extension functions. Macromers are polymerized using free radical initiators under the influence of long wavelength ultraviolet light, visible light excitation or thermal energy. Biodegradation occurs at the linkages within the extension oligomers and results in fragments which are non-toxic and easily removed from the body. Preferred applications for the hydrogels include prevention of adhesion formation after surgical procedures, controlled release of drugs and other bioactive species, temporary protection or separation of tissue surfaces, adhering of sealing tissues together, and preventing the attachment of cells to tissue surfaces.Type: GrantFiled: January 27, 1995Date of Patent: May 6, 1997Assignee: Board of Regents, The University of Texas SystemInventors: Jeffrey A. Hubbell, Chandrashekhar P. Pathak, Amarpreet S. Sawhney, Neil P. Desai, Jennifer L. Hill