Impra, Inc.,

Robert W Calcote

Rajagopal R Kowligi

Stacy Wollner

An improved ePTFE-based delivery graft is intended to dispense a bioactive agent such as a drug into the blood stream. A hollow tubing is infused with the agent from a source such as a drug delivery pump mechanism. The spiral hollow tubing is wrapped in a helical fashion around, or otherwise brought into contact with an outer wall of a porous ePTFE graft and adhered thereto. The agent is delivered to the lumen of the graft by infusing the agent through the porous interstices of the graft wall. Thus, the bioactive agent is conducted by the hollow tubing from a source to the outer surface of an ePTFE graft where it is released to diffuse into the graft to influence biological processes along both the inner and outer surfaces of the graft. The present invention allows the bioactive agent or drug to be renewed or changed after implant of the graft. In addition the present invention can be implanted in the same fashion as regular vascular grafts.

Expanded PTFE drug delivery graft

A dual porosity PTFE tube including an inner surface of expanded PTFE material having a first porosity and an outer surface of expanded PTFE material having a porosity different from that of the inner surface. The preferred method includes the step of forming inner and outer preformed tubular billets of PTFE resin particles mixed with a lubricant; the outer billet is adapted to closely fit around and concentric to the inner billet. Porosity of the inner and outer surfaces is varied by changing, in the respective billets, the lubrication level and/or the PTFE resin characteristic average particle size. The inner billet is placed inside the outer billet, and the two are extruded together, thereby melding the two billets. The extrudate is then longitudinally expanded and sintered. The inner surface of the resulting PTFE tube exhibits a different porosity than the outer surface of the tube; the porosities of the inner and outer surfaces are both within a range of about 0.10-200 .mu..

Dual porosity PTFE tubes

Method of forming dual porosity PTFE tubes by extrusion of concentric

A dual porosity PTFE tube including an inner surface of expanded PTFE material having a first porosity and an outer surface of expanded PTFE material having a porosity different from that of the inner surface. The preferred method includes the step of forming inner and outer preformed tubular billets of PTFE resin particles mixed with a lubricant; the outer billet is adapted to closely fit around and concentric to the inner billet. Porosity of the inner and outer surfaces is varied by changing, in the respective billets, the lubrication level and/or the PTFE resin characteristic average particle size. The inner billet is placed inside the outer billet, and the two are extruded together, thereby melding the two billets. The extrudate is then longitudinally expanded and sintered. The inner surface of the resulting PTFE tube exhibits a different porosity than the outer surface of the tube; the porosities of the inner and outer surfaces are both within a range of about 0.10-200.mu..

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Phoenix, AZ, United States of America

Robert W Calcote