# US 5,980,551 A · Composition and method for making a biodegradable drug delivery stent > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,980,551 A - Document ID: US5980551A - Status: Granted - Kind: A - Application number: 08/797,743 - Filed: 1997-02-07 - Granted: 1999-11-09 - Earliest claimed: 1997-02-07 - Assignees: Endovasc Ltd., Inc. - Inventors: David P. Summers; Jackie R. See - Web page: https://patentgrep.com/patent/US5980551A ## CPC - A61F 2/885: {comprising a coil including a plurality of spiral or helical sections with alternate directions around a central axis} - A61L 31/10: Macromolecular materials - A61L 31/16: Biologically active materials, e.g. therapeutic substances {(A61L31/047 takes precedence)} - A61F 2/0077: {Special surfaces of prostheses, e.g. for improving ingrowth (A61F2/30767 takes precedence)} - A61F 2/07: Stent-grafts - A61F 2002/072: {Encapsulated stents, e.g. wire or whole stent embedded in lining} - A61L 2300/22: Lipids, fatty acids, e.g. prostaglandins, oils, fats, waxes - A61L 2300/416: Anti-neoplastic or anti-proliferative or anti-restenosis or anti-angiogenic agents, e.g. paclitaxel, sirolimus - A61L 2300/606: Coatings - A61L 2300/622: Microcapsules - A61L 2300/626: Liposomes, micelles, vesicles - A61M 2025/0057: {Catheters delivering medicament other than through a conventional lumen, e.g. porous walls or hydrogel coatings} - A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C) - A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K) - A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)} ## Abstract A stent or vascular graft for supporting a blood vessel or organ lumen is coated with a biodegradable, resorbable and hemocompatible surface substrate. Biologically active microspheres which controllably release the biologically active agent into the vessel wall or organ to inhibit restenosis of the stent is embedded in the stent substrate. The biologically active microspheres include encapsulated PGE1 in a water soluble polyethylene glycol mix, which over a period of time dissolves and releases the PGE1 into the vessel wall or organ. ## Claims ### Claim 1 A stent for supporting a blood vessel, comprising: (a) a stent body; (b) a biodegradable, porous stent substrate swelled in 40% trifluoacetic acid with polyethylene oxide applied on said stent body, wherein the pores of said stent substrate are opened upon swelling said stent substrate; and (c) a polymer mixture coating said stent substrate, said polymer mixture including biologically active microspheres, and wherein said polymer mixture fills and collapes the pores of said stent substrate. ### Claim 2 (depends on 1) The stent of claim 1 wherein said substrate comprises one or more layers of a resorbable PLLA/PLC mixture encapsulating said stent body. ### Claim 3 (depends on 2) The stent of claim 2 wherein said water soluble polymer mixture comprises a slurry of polyethylene glycol (PEG) and liposomes carrying a biologically active agent. ### Claim 4 (depends on 1) The stent of claim 1 wherein said stent substrate comprises a Poly-L-lactic acid/Polycaprolactone mixture encapsulating said stent body, and wherein said polymer mixture comprises a Polyethylene glycol/lyophilized liposome surface coating on said stent body, and wherein the liposomes in said surface coating range in average diameter from about 100 nm to 200 nm. ### Claim 5 (depends on 2) The stent of claim 2 wherein said stent substrate and said polymer mixture are water soluble and resorbable, providing a continuous and gradual release of prostaglandin encapsulated in said biologically active microspheres. ### Claim 6 (depends on 1) The stent of claim 1 wherein the pores of said stent substrate define an irregular pore surface for releaseably retaining said biologically active microspheres, and wherein said microspheres contain prostaglandin E1 encapsulated in said microspheres. ### Claim 7 (depends on 6) The stent of claim 6 wherein the pores of said stent substrate have a mean pore size of 150 nm to 200 nm long axis and 50 nm to 75 nm short axis. ### Claim 8 (depends on 7) The stent of claim 7 wherein said microspheres release prostaglandin E1 at a controlled rate for up to six months. ### Claim 9 (depends on 1) The stent of claim 1 wherein said stent substrate has a porosity of 18% to 45%. ### Claim 10 A method of modifying cellular response in a blood vessel or organ to a disease, injury or foreign body, comprising the steps of: a) forming a water soluble and resorbable hemocompatible stent coating; b) swelling said stent coating in 40% trifluoacetic acid with polyethylene oxide to open the pores of said stent coating; c) embedding microspheres having a biologically active agent encapsuled in said microspheres in said stent coating; d) applying said stent coating on a stent body; e) positioning said stent body in the blood vessel or organ; and f) controllably releasing said biologically active agent into the blood vessel wall or target organ.