Drug coating layer

Abstract

Provided are a drug coating layer which has low toxicity and a high intravascular stenosis inhibitory effect, when delivering medical device coated with a drug into the body and medical device using the same. The drug coating layer is a drug coating layer having a morphological form including a plurality of elongated bodies having long axes that each crystal of a water-insoluble drug independently has on a substrate surface, in which the long axes of the elongated bodies are nearly linear in shape, and the long axes of the elongated bodies form an angle in a predetermined range with respect to a substrate plane with which the long axis of the elongated body intersects.

What is claimed is: 
     
         1 . A drug coating layer having a morphological form including a plurality of elongated bodies of independent crystals of a water-insoluble drug having longitudinal axes on a substrate surface,
 wherein the longitudinal axes of the elongated bodies are generally linear in shape, and the longitudinal axes of the elongated bodies form an angle in a predetermined range with respect to a substrate plane with which the long axis of the elongated body intersects.   
     
     
         2 . The drug coating layer according to  claim 1 ,
 wherein at least a vicinity of the distal of the elongated body is hollow.   
     
     
         3 . The drug coating layer according to  claim 1 ,
 wherein a cross-sectional shape of the elongated body on a surface perpendicular to the longitudinal axis is a polygon.   
     
     
         4 . The drug coating layer according to  claim 3 ,
 wherein the polygon is selected from the group consisting of a tetrahedron, a pentagon and a hexagon.   
     
     
         5 . The drug coating layer according to  claim 4 ,
 wherein the polygon is a tetrahedron.   
     
     
         6 . The drug coating layer according to  claim 1 ,
 wherein the angle is in the range of 45 to 135° with respect to the substrate plane.   
     
     
         7 . The drug coating layer according to  claim 6 ,
 wherein the angle is in the range of 70 to 110° with respect to the substrate plane.   
     
     
         8 . The drug coating layer according to  claim 6 ,
 wherein the angle is in the range of 80 to 100° with respect to the substrate plane.   
     
     
         9 . The drug coating layer according to  claim 1 ,
 wherein the elongated bodies have a length in the direction of the longitudinal axis of 5 to 20 μm.   
     
     
         10 . The drug coating layer according to  claim 9 ,
 wherein the elongated bodies have a length in the direction of the longitudinal axis of 9 to 11 μm.   
     
     
         11 . The drug coating layer according to  claim 1 ,
 wherein the elongated bodies have a diameter perpendicular to the longitudinal axis of 0.01 to 5 μm.   
     
     
         12 . The drug coating layer according to  claim 11 ,
 wherein the elongated bodies have a diameter perpendicular to the longitudinal axis of 0.05 to 4 μm.   
     
     
         13 . The drug coating layer according to  claim 11 ,
 wherein the elongated bodies have a diameter perpendicular to the longitudinal axis of 0.1 to 3 μm.   
     
     
         14 . A drug coating layer in which flatly elongated hair shaped crystals of a water-insoluble drug are randomly laminated on a substrate surface,
 wherein longitudinal axes of the crystals partly have a curved portion, and crystals having other shapes are not mixed in the same crystal plane.   
     
     
         15 . The drug coating layer according to  claim 14 ,
 wherein a surface of the crystal of the water-insoluble drug is further covered with an amorphous film.   
     
     
         16 . The drug coating layer according to  claim 14 ,
 wherein the flatly elongated hair shaped crystals have a length in a long axis of 10 to 100 μm.   
     
     
         17 . A drug coating layer comprising:
 a crystalline morphological form of a water-insoluble drug;   the drug coating layer comprising crystalline particles of the water-insoluble drug configured to be arranged with regularity on the substrate surface; and   excipient particles comprised of an excipient configured to be irregularly arranged between the crystalline particles,   wherein a molecular weight of the excipient is less than a molecular weight of the water-insoluble drug, a ratio occupied by the excipient particles per a predetermined area of a substrate is less than a ratio occupied by the crystalline particles, and the excipient particles do not form a matrix.   
     
     
         18 . The drug coating layer according to  claim 1 ,
 wherein the water-insoluble drug is rapamycin, paclitaxel, docetaxel, or everolimus.   
     
     
         19 . A medical device having the drug coating layer according to  claim 1  on the surface of the medical device, wherein the medical device is reduced in diameter to be delivered when delivered into a body, and is enlarged in diameter to release a drug from the drug coating layer at an affected part. 
     
     
         20 . A method for delivering a drug, comprising:
 delivering the medical device according to  claim 19  to a lumen;   radially dilating a dilatable portion provided in the medical device; and   applying the drug coating layer which the dilatable portion has to the lumen.