Endoluminal device for in vivo delivery of bioactive agents
View Patent ↗The present invention consists of an implantable structural element for in vivo delivery of bioactive active agents to a situs in a body. The implantable structural element may be configured as an implantable prosthesis, such as an endoluminal stent, cardiac valve, osteal implant or the like, which serves a dual function of being prosthetic and a carrier for a bioactive agent. Alternatively, the implantable structural element may simply be an implantable article that serves the single function of acting as a time-release carrier for the bioactive agent.
1. A method of making an implantable device comprising:
a. forming a base layer of structural material;
b. depositing a pattern of sacrificial material onto the base layer, the sacrificial material forming internal cavity regions;
c. depositing at least a second layer of structural material over the sacrificial material and over the base layer forming a strut having a an upper surface, lower surface, and lateral surface bounding the sacrificial material;
d. forming one or more microholes in the structural material providing fluid flow communication between the sacrificial material and the area external to the at least one of upper surface, lower surface, or lateral surface; and
e. removing the sacrificial material forming at least one internal cavity bound intermediate the upper surface, lower surface, and lateral surface wherein the one or more microholes are in fluid communication with the internal cavity.
2. The method of claim 1 , wherein the step of removing the sacrificial material forming at least one internal cavity is performed by etching.
3. The method of claim 1 , wherein the strut formed is planar.
4. The method of claim 1 , wherein the step of forming one or more holes in the structural material comprises one of the methods of formation selected from the group consisting of microdrilling, laser cutting, etching, and EDM.
5. The method of claim 1 , wherein the step of forming a base layer of structural material, comprises using a vacuum deposition technique selected from the group consisting of sputtering, reactive ion etching, chemical vapor deposition, and plasma vapor deposition.
6. The method of claim 1 , further comprising the step of depositing a bioactive agent within the internal cavity.
7. The method of claim 6 , wherein the step of removing the sacrificial material forming the region of the internal cavity is performed by etching.
8. The method of claim 6 , further comprising the step of forming regions of one or more holes with sacrificial material, wherein the step of forming one or more holes in the structural material comprises removing the sacrificial material forming the regions of one or more holes by etching.
9. The method of claim 8 , wherein the step of depositing a second layer of structural material over the sacrificial material does not include depositing structural material over the sacrificial material forming regions of one or more holes.
10. The method of claim 6 , wherein a plurality of struts are formed resulting in a generally tubular shaped stent structure.
11. An endoluminal stent, comprising:
a. a plurality of tubular struts, each tubular strut of the plurality of tubular struts having an external surface, an internal surface, a wall thickness intermediate the external and internal surfaces that is substantially uniform about a transverse cross section of the tubular strut, and an internal cavity concentric entirely within the tubular strut along a longitudinal axis of the tubular strut;
b. a plurality of micropores passing through the wall thickness distributed about the entire circumference of the tubular strut that permit generally omnidirectional fluid flow therethrough from the internal cavity;
c. a bioactive agent disposed within the internal cavity that elutes from the internal cavity through at least some of the plurality of micropores; and
d. wherein the plurality of struts are disposed circumferentially forming a tubular stent having a stent central lumen.
12. The endoluminal stent of claim 11 , wherein the plurality of tubular struts are operably associated with one another in such a manner as to permit diametric expansion of the endoluminal stent.
13. The endoluminal stent of claim 12 , wherein the plurality of tubular struts are in a configuration selected from the group consisting of a grid configuration, a mesh configuration, and a braided configuration.
14. The endoluminal stent of claim 11 , wherein the plurality of micropores are dimensioned to permit a bioactive agent to elute from the internal cavity and through the plurality of micro-openings by diffusion, osmotic pressure, under the influence of a positive pressure applied by cellular in-growth into the internal cavity, or under positive pressure applied by stress and/or strain exerted on the at least one cavity due to deformation of the tubular strut.