An implantable medical device is disclosed, comprising: an implantable device body 10 having a plurality of through holes 20 therein a barrier layer 66 formed in the plurality of through holes 20, the barrier layer 66 formed of a biodegradable copolymer having a copolymer ratio a drug filled portion 60, 62 formed in the plurality of through holes 20 adjacent the barrier layer 66 and a cap layer 64 formed in the plurality of holes 20 adjacent the drug filled portion 60, 62, wherein said cap layer 64 is different from said barrier layer 66.
