a conjugate between an anti - thrombotic agent and a bioabsorbable polymer is provided . in addition , a method is provided for applying a coating comprising an anti - thrombotic agent and a bioabsorbable polymer conjugate to at least a portion of an implantable device to prevent or reduce the formation of thrombosis on the surface of the device . a first or sub - layer of the coating is prepared by mixing a polymeric material and a biologically active agent with a solvent , thereby forming a homogeneous solution . a second or outer layer comprises an anti - thrombotic heparin - bioabsorbable polymer conjugate . this coating may be applied over the inner drug - containing layers using , for example , a dip coating or spray coating process . after drying , the anti - thrombotic heparin bioabsorbable polymer conjugate remains in the outer layer of the coating , allowing agent from the inner layer to be eluted there through . in addition , the outmost layer prevents the formation of thrombosis , and also serves to modulate the release kinetics of the agent contained within an inner layer of the coating .