Methods To Increase Fracture Resistance Of A Drug-Eluting Medical Device

{
  "publication_number": "US2010323091A1",
  "country": "US",
  "kind": "A1",
  "title": "Methods To Increase Fracture Resistance Of A Drug-Eluting Medical Device",
  "abstract": "Methods for increasing the fracture resistance of a polymer stent's drug-polymer coating and scaffolding including applying a coating and crimping using techniques that increase the resistance to fracture in the coating layer and scaffolding and scaffolding.",
  "claims": [
    "1. A method for forming a drug-eluting stent coating forming a stent from a polymer tube having a diameter approximately equal to the maximum deployed diameter for the stent when implanted within a vessel crimping the stent body down to an intermediate diameter applying a drug-polymer coating to the stent body while it is at the intermediate diameter; and after applying the drug-polymer coating crimping the stent body down to a delivery diameter. 2. A method for increased fracture resistance in a drug-eluting polymer stent having a deployed diameter and a stowed diameter, comprising the steps of: radially expanding an extruded polymer tube to a starting diameter that is greater than the stent's deployed diameter; forming a stent scaffolding from the tube; reducing the diameter of the scaffolding to about 50-80% of the starting diameter; spraying a solution comprising a drug-polymer dissolved in a solvent on the surface of the scaffolding, wherein the sprayed solution is between 90-98% solvent by weight; baking the scaffolding having the drug-polymer thereon for a first relaxation period; and crimping the stent down to its stowed diameter including a plurality of intermediate crimping steps, wherein at least one intermediate crimping step is followed by a second relaxation period. 3. The method of claim 2, wherein the scaffolding has W shaped elements. 4. The method of claim 3, wherein a strut turns through an angle of greater than 130 degrees when the stent is expanded from a stowed configuration to a deployed configuration. 5. The method of claim 2, wherein the spraying step includes applying a plurality of solutions of about 90-98% solvent by weight including an intermediate forced air drying to remove solvent until a final coating weight is reached. 6. The method of claim 5, wherein the baking step includes temperature of about 5-20 degrees below the glass transition temperature for the coating polymer for about 15-60 minutes. 7. The method of claim 6, wherein the coating polymer is PDLA and the scaffolding polymer is PLLA or PLGA. 8. The method of claim 7, wherein the ratio of deployed to stowed diameters is between 2:1 and 5:1. 9. The method of claim 1, wherein the polymer of the drug-polymer is PDLA. 10. The method of claim 2, wherein the polymer of the drug-polymer is PDLA. 11. The method of claim 1, wherein the scaffolding polymer is selected from the set consisting of PGLA or PDLA. 12. The method of claim 2, wherein the scaffolding polymer is selected from the set consisting of PGLA or PDLA."
  ],
  "cpc": [
    "A61L 31/08",
    "A61F 2/06",
    "A61F 2/91",
    "A61F 2/915",
    "A61F 2/9522",
    "A61F 2002/91558",
    "A61F 2002/91566",
    "A61F 2002/91575",
    "A61F 2240/001",
    "A61F 2250/0067",
    "B05D 1/34",
    "Y10T 29/49913"
  ],
  "assignees": [
    "ABBOTT CARDIOVASCULAR SYSTEMS"
  ],
  "filing_date": "2009-06-23",
  "publication_date": "2010-12-23",
  "priority_date": "2009-06-23",
  "application_number": "US-49024809-A",
  "family_id": "42561237",
  "citations": [
    "US2006287715A1",
    "US2007208416A1",
    "US2007271763A1",
    "US2007281073A1",
    "US2010241220A1",
    "US4977901A",
    "US5980972A"
  ]
}