a first embodiment of the present invention will be explained in the following with the aid of the fig1 to 6 in more detail . fig1 shows schematically a balloon catheter 1 that by means of a spraying device 5 is sprayed with the solution 6 of an active ingredient 7 in a solvent 8 that is miscible with water . the balloon catheter 1 comprises a catheter probe 2 and a balloon 3 . the balloon 3 surrounds a portion of the catheter probe 2 . the balloon 3 is comprised of a polymer , for example , nylon or a nylon pebax mixture . the surface of the balloon 3 is wetted by means of a spraying device 5 with a solution 6 of an active ingredient 7 in a solvent 8 that is miscible with water and in this way is wetted . in place of the spraying action the balloon 3 of the balloon catheter 1 can also be immersed in a solution of an active ingredient in a solvent that is miscible with water or can be pipetted with it . the solvent 8 has the effect that the surface of the balloon 3 is softened . basically , the surface of the balloon 3 can also be softened first , for example , by means of a softening agent , and subsequently can be wetted with a solution of an active ingredient 6 . fig2 shows schematically a section of a part of the surface of the balloon 3 of the balloon catheter 1 whose surface is wetted with the solution of an active ingredient 7 . the area of the surface 4 that is softened by the solvent 8 is referenced by reference numeral 12 . on the softened surface 4 of the balloon 3 there is a mixture of a solvent 8 and an active ingredient 7 . the employed active ingredient 7 can be , for example , tretinoin and / or tretinoin derivatives and / or orphan receptor agonists and / or elafin derivatives and / or corticosteroids and / or steroid hormones and / or paclitaxel and / or taxol and / or taxol derivatives and / or rapamune and / or tacrolimus and / or hydrophobic proteins and / or substances that change cell proliferation , wherein as steroid hormones methyl prednisolone , dexamethasone or estradiol can be used . the solvent 8 can be , for example , dimethyl sulfoxide ( dmso ), dioxane , dimethyl formamide ( dmf ), tetrahydrofuran ( thf ), methylene chloride or chloroform . after wetting the surface 4 , the solvent is evaporated or allowed to evaporate . during this time the active ingredient 7 in its entirety or partially is embedded into the softened surface 4 . this is indicated schematically in fig3 . fig3 shows a section of a part of surface 4 of a balloon 3 of balloon catheter 1 having embedded in its surface 4 an active ingredient 7 a , 7 b . the active ingredient that is partially embedded in the surface 4 is referenced by reference numeral 7 a and the active ingredient that is embedded completely into the surface 4 is referenced by reference numeral 7 b . a second embodiment variant of the first embodiment is explained in more detail in the following with the aid of fig4 and 5 . in this embodiment variant the balloon 3 is first softened , as described in connection with fig1 and 2 , and is wetted with a solution of an active ingredient 6 . subsequently , in contrast to the afore described embodiment variant , the solvent 8 is not evaporated but the active ingredient 7 is deposited by precipitation on the softened surface 4 . fig4 shows schematically the immersion of the balloon catheter wetted with the solution of an active ingredient 6 in a water bath . in fig4 , a vessel 10 is illustrated that is filled with water 9 . the balloon 3 of the balloon catheter 1 is completely immersed in the water 9 . the softened and wetted surface 4 of the balloon 3 is in direct contact with the water 9 . fig5 shows schematically a section of a part of the softened surface 4 of the balloon 3 of catheter of the balloon catheter 1 which is located in water 9 . as a result of the direct contact between the water 9 and the solvent 8 that is miscible with water an increasing mixing of the solvent 8 with water 9 takes place . this is schematically indicated in fig5 . the active ingredient 7 that is insoluble in water or at least only soluble with difficulty in water will precipitates , on the other hand , on the softened surface 4 of the balloon 3 and is embedded therein , as disclosed in connection with fig3 . in this way , the active ingredient 7 is separated from the solvent 8 . after the active ingredient 7 has precipitated on the surface 4 the balloon 3 of the balloon catheter 1 can be removed from the water bath . the water that may still be present on the surface 4 of the balloon 3 may subsequently be allowed to evaporate . however , as a result of embedding of the active ingredient 7 in the surface 4 , the active ingredient 7 is already fixedly connected to the surface 4 of the balloon 3 so that the balloon 3 in principle must not be dried i . e ., may remain wet . subsequently , a third embodiment variant of the first embodiment will be explained in more detail with the aid of fig6 . in this embodiment variant the surface 4 of the balloon 3 is first roughened before being softened . this can be done in particular mechanically , chemically , or thermally . in this connection , on the surface 4 of the balloon 3 in particular depressions with a depth of 5 - 50 μm and width of 5 - 50 μm can be generated . subsequently , the roughened surface 13 of the balloon 3 , as disclosed in the first two embodiment variants , can the softened and wetted with the solution of an active ingredient 6 . after the solvent 8 has been separated , for example , by allowing it to evaporate or by precipitation , from the active ingredient 7 , the active ingredient is embedded entirely or partially in the roughened surface 13 of the balloon 3 . this is schematically indicated in fig6 . fig6 shows schematically a section of a part of the surface 13 of a balloon 3 of a balloon catheter 1 having embedded in its roughened surface 13 the active ingredient 7 . the active ingredient embedded partially in the surface 13 is referenced with reference numeral 7 a , the completely embedded active ingredient is referenced with reference numeral 7 b . in the following , a second embodiment will be explained with the aid of fig7 to 10 in more detail . elements that correspond to such elements that have already been explained in connection with the first embodiment are identified with the same reference numerals and are not described again in detail . the instant embodiment relates to a stent that is coated with an active ingredient 7 . in this connection , the stent is a polymer stent . fig7 shows schematically a section of a part of a screen structure 14 of a stent whose surface 15 is softened and wetted with a solution of an active ingredient as described in connection with fig1 . the softened part of the surface 15 of the screen structure 14 is referenced with reference numeral 12 . as a solvent 8 or active ingredient 7 the substances mentioned in connection with the first embodiment can be employed . subsequently , the solvent 8 is separated either by allowing it to evaporate or by precipitation from the active ingredient 7 wherein the active ingredient 7 becomes embedded in the surface of the screen structure 14 . with respect to details in this regard reference is being had to the embodiment variants of the first embodiment . fig8 shows schematically a section of a part of a screen structure 14 of a stent having embedded in its surface 15 an active ingredient 7 . the active ingredient that is partially embedded in the surface 15 is referenced by reference numeral 7 a , the completely embedded active ingredient is referenced by reference numeral 7 b . in the following , a second embodiment variant of the second embodiment is described in more detail in connection with fig9 and 10 . in contrast to the afore described embodiment variant the stent 14 , which in this case must not be a polymer stent , is first functionally coated with a polymer layer 16 . for this purpose , for example on the stent 14 the dimeric 4 - amino -[ 2 , 2 ]- paracyclophane is cleaved at 700 ° c . and 20 pa into reactive monomers and polymerizes subsequently on the surface of the stent 14 that is cooled to approximately 20 ° c . the desired thickness of the polymer coating is advantageously 10 - 1 , 000 μm , even more advantageous 200 - 400 μm . the thus generated polymer layer 16 can now either be softened and wetted directly with a solution 6 of an active ingredient 7 in a solvent 8 that is miscible with water , as disclosed in the first embodiment in connection with fig1 . in addition , the surface area of the polymer coating 16 can be enlarged prior to softening and wetting , for example , by roughening . the possibilities for enlarging the surface area of the balloon 3 disclosed in detail in the first embodiment are also suitable for a possible enlargement of the surface area of the polymer coating 16 in the present embodiment . the roughened surface of the polymer coating 16 is subsequently , as disclosed in connection with the first embodiment , wetted with a solution 6 of an active ingredient 7 in a solvent 8 miscible with water and softened at the same time . fig9 shows schematically a section of a part of a screen structure 14 of a stent that was coated with a polymer 16 and that has on its softened polymer surface the solution of the active ingredient 7 . the softened area of the polymer coating 16 is referenced with the reference numeral 12 . as a solvent 8 or active ingredient 7 the substances that have been mentioned in the first embodiment can be employed . the solvent 8 that is located on the softened and wetted surface of the polymer coating 16 can be selectively allowed to evaporate or the stent , as explained in the first embodiment in connection with fig4 and 5 based on the example of the balloon 3 , can be immersed in a water bath whereupon the active ingredient 7 will precipitate on the polymer - coated surface and will be embedded therein . in case of evaporation , in all described embodiments and embodiment variants the use of a solvent that is immiscible with water or only soluble with difficulty in water is possible also . embedding of the active ingredient 7 in the polymer coating 16 obtained in the described way is schematically illustrated in fig1 . fig1 schematically shows a section of a part of a screen structure 14 of a stent that is coated functionally with a polymer 16 and that has embedded in its polymer coating 16 an active ingredient 7 . the active ingredient embedded partially in the polymer coating 16 is referenced by reference numeral 7 a , the completely embedded active ingredient is referenced by reference numeral 7 b .
a method for producing a bioactive surface on an endoprosthesis , or on the balloon of a balloon catheter is described , wherein the surface of the endoprosthesis , or the surface of the balloon is softened . the surface of the endoprosthesis , or the surface of the balloon is moistened with a solution of an active ingredient , and the solvent is separated from the active ingredient . in addition , a balloon of a balloon catheter is disclosed , which comprises an uncoated surface , wherein an unencapsulated active ingredient is embedded at least partially into the material of the surface . furthermore , a balloon catheter is described , which comprises a balloon according to the invention . in addition , an endoprosthesis , particularly a polymer stent is described , which comprises an uncoated surface , wherein an active ingredient is embedded at least partially into the material of the surface .