An implantable medical device is provided for controlled drug delivery withinthe bladder, or other body vesicle.The dev ice may include at least one drug reservoir component comprising adrug； and a esieie retention frame which comprisesan elastic wire having a first end, an opposing second end. and anintermediate region therebetween. wherein the drug reservoircomponent is attached to lhe intermediate region of the vesicle retentionframe. The retention frame prevents accidental voiding ofthe device from the bladder, and it preferably has a spring constant selectedfor the device to effectively stay in the bladder duringurination while rainimi/ine the irritation of the bladder.
