Biodegradable stent

{
  "publication_number": "US6537312B2",
  "country": "US",
  "kind": "B2",
  "title": "Biodegradable stent",
  "abstract": "A biodegradable stent for implantation into a lumen in a human body. The stent in one embodiment is made from a biodegradable fiber having an inner core and an outer layer. The outer layer is a blend of two polymer components. The inner core has a first degradation rate, and the outer layer has a second degradation rate. The second degradation rate is slower than the first degradation rate. The fiber softens in vivo such that the stent is readily passed from the lumen as a softened fragment or filament after a pre-determined period of time through normal flow of body fluids passing through the lumen.",
  "claims": [
    "1. A stent, comprising: an elongated structure having a longitudinal passage, said structure comprising: a blend of a first biodegradable polymer component and a second biodegradable polymer component, said first polymer component comprising a first biodegradable polymer, wherein said first biodegradable polymer comprises a lactide/glycolide copolymer having at least about 80 mole percent of polymerized glycolide, said second polymer component comprising a second biodegradable polymer; wherein said second biodegradable polymer comprises a lactide-rich copolymer comprising at least about 50 mole percent of polymerized lactide, wherein the blend comprises at least about 50 weight percent of the first component and at least about 5 weight percent of the second component, said blend having an in vivo degradation rate, wherein said structure degrades by softening.",
    "2. The stent of claim 1, further comprising an inner core having a second degradation rate, said second degradation rate being faster than the degradation rate of the blend.",
    "3. The stent of claim 2 comprising a tubular structure.",
    "4. A method of maintaining a passageway of a body lumen substantially open, comprising the steps of: providing a biodegradable stent, said stent comprising: a tubular structure having a longitudinal passage, said structure comprising: an inner core having an exterior surface comprising a biodegradable polymer formed from monomers selected from the group consisting of lactide, glycolide, para-dioxanone, trimethylene carbonate, caprolactone, and combinations thereof, said polymer having a first degradation rate; an outer section covering the exterior surface of the inner core, the outer section comprising a comprising a blend of a first biodegradable polymer component and a second biodegradable polymer component, said first polymer component comprising a first biodegradable polymer, wherein said first biodegradable polymer comprises a lactide/glycolide copolymer having at least about 80 mole percent of polymerized glycolide, said second polymer component comprising a second biodegradable polymer, wherein said second biodegradable polymer comprises a lactide-rich copolymer comprising at least about 50 mole percent of polymerized lactide, said outer layer having a second degradation rate, wherein the blend comprises at least about 50 weight percent of the first component and at least about 5 weight percent of the second component; and, inserting said stent into a body lumen, wherein said second degradation rate is lower than said first degradation rate, and said outer layer degrades into a soft, fibrillar morphology."
  ],
  "description_excerpt": "This application is a division of application Ser. No. 09/470,619, filed Dec. 22, 1999.\n\nThe field of art to which this invention relates is medical devices, in particular, stent devices made from biodegradable polymers.\n\nThe use of stent medical devices, or other types of endoluminal mechanical support devices, to keep a duct, vessel or other body lumen open in the human body has developed into a primary therapy for lumen stenosis or obstruction. The use of stents in various surgical procedures has quickly become accepted as experience with stent devices accumulates, and the number of surgical procedures employing them increases as their advantages become more widely recognized. For example, it is known to use stents in body lumens in order to maintain open passageways such as the prostatic urethra, the esophagus, the biliary tract, intestines, and various coronary arteries and veins, as well as more remote cardiovascular vessels such as the femoral artery, etc. There are two types of stents that are presently utilized: permanent stents and temporary stents. A permanent stent is designed to be maintained in a body lumen for an indeterminate amount of time. Temporary stents are designed to be maintained in a body lumen for a limited period of time in order to maintain the patency of the body lumen, for example, after trauma to a lumen caused by a surgical procedure or an injury. Permanent stents are typically designed to provide long-term support for damaged or traumatized wall tissues of the lumen.",
  "cpc": [
    "A61L 31/148",
    "A61F 2/88",
    "A61F 2210/0004",
    "A61L 31/041",
    "A61L 31/06",
    "A61L 31/10",
    "A61L 31/14"
  ],
  "ipc": [
    "A61F 2/06",
    "A61F 2/84",
    "A61F 2/88",
    "A61L 31/00",
    "A61L 31/04",
    "A61L 31/06",
    "A61L 31/10",
    "A61L 31/14",
    "C08L 101/16",
    "D01F 8/14"
  ],
  "assignees": [
    "Ethicon Inc"
  ],
  "inventors": [
    "Arindam Datta",
    "Shawn Thayer Huxel",
    "Dennis D. Jamiolkowski",
    "Yufu Li"
  ],
  "filing_date": "2001-08-20",
  "publication_date": "2003-03-25",
  "grant_date": "2003-03-25",
  "priority_date": "1999-12-22",
  "application_number": "US-93305901-A",
  "family_id": "23868330",
  "cited_by_count": 107,
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}