Shaped monolithic controlled release device for improved drug release in implantable medical leads and leadless pacemakers

Abstract

A monolithic controlled release device (MCRD) for use with an implantable medical device includes a distal face, a proximal face opposite the distal face, and an outer circumferential surface extending between the distal face and the proximal face. A spline-shaped inner lumen extends between the distal face and the proximal face and radially inward from the outer circumferential surface. The MCRD is formed from a mixture including an active pharmaceutical ingredient.

What is claimed is: 
     
         1 . A monolithic controlled release device (MCRD) for use with an implantable medical device, the MCRD comprising:
 a distal face;   a proximal face opposite the distal face;   an outer circumferential surface extending between the distal face and the proximal face; and   a spline-shaped inner lumen extending between the distal face and the proximal face and radially inward from the outer circumferential surface,   wherein the MCRD is formed from a mixture including an active pharmaceutical ingredient.   
     
     
         2 . The MCRD of  claim 1 , wherein the spline-shaped inner lumen includes ridges extending longitudinally along an inner surface of the spline-shaped inner lumen. 
     
     
         3 . The MCRD of  claim 2 , wherein the spline-shaped inner lumen further includes grooves extending longitudinally along the inner surface of the spline-shaped inner lumen. 
     
     
         4 . The MCRD of  claim 3 , wherein the ridges and grooves are circumferentially dispersed along an inner circumference of the spline-shaped inner lumen in an alternating arrangement. 
     
     
         5 . The MCRD of  claim 3 , wherein the ridges project radially inward towards a longitudinal center line of the spline-shaped inner lumen. 
     
     
         6 . The MCRD of  claim 5 , wherein the ridges are radiused. 
     
     
         7 . The MCRD of  claim 3 , wherein the grooves extend radially outward from a longitudinal center line of the spline-shaped inner lumen and into a wall structure of the MCRD. 
     
     
         8 . The MCRD of  claim 7 , wherein the grooves terminate at planar bottoms. 
     
     
         9 . The MCRD of  claim 8 , wherein the planar bottoms are rectangular. 
     
     
         10 . The MCRD of  claim 1 , wherein the distal face and proximal face are planar, and the outer circumferential surface is cylindrical and smooth. 
     
     
         11 . The MCRD of  claim 1 , wherein at least one of the distal face, the proximal face, or the outer circumferential surface is ridged and grooved. 
     
     
         12 . The MCRD of  claim 1 , wherein the spline-shaped inner lumen includes eight ridges and eight grooves arranged in equal alternating fashion about an inner circumference of the spline-shaped inner lumen. 
     
     
         13 . The MCRD of  claim 12 , wherein the eight ridges are circumferentially spaced apart from each other by an angle of 45 degrees. 
     
     
         14 . The MCRD of  claim 1 , wherein the MCRD is injection molded and the mixture further comprises liquid silicone rubber. 
     
     
         15 . The MCRD of  claim 1 , wherein the active pharmaceutical ingredient includes at least one of Dexamethasone Sodium Phosphate or Dexamethasone Acetate. 
     
     
         16 . A monolithic controlled release device (MCRD) for use with an implantable medical device, the MCRD comprising:
 a distal face;   a proximal face opposite the distal face;   an outer circumferential surface extending between the distal face and the proximal face; and   an inner lumen extending between the distal face and the proximal face and radially inward from the outer circumferential surface, the inner lumen comprising at least one of a ridge or a groove extending longitudinally along an inner surface of the inner lumen.   
     
     
         17 . The MCRD of  claim 16 , wherein the at least one of the ridge or the groove extends radially inward or outward, respectively, relative to a longitudinal center line of the inner lumen. 
     
     
         18 . The MCRD of  claim 16 , wherein the at least one of the ridge or the groove comprises the ridge and the ridge is radiused. 
     
     
         19 . The MCRD of  claim 16 , wherein the at least one of the ridge or the groove comprises the groove and the groove terminates in a planar bottom. 
     
     
         20 . A monolithic controlled release device (MCRD) for use with an implantable medical device, the MCRD comprising:
 a distal face;   a proximal face opposite the distal face;   an outer circumferential surface extending between the distal face and the proximal face; and   a non-cylindrical inner lumen extending between the distal face and the proximal face and radially inward from the outer circumferential surface.