this combination construction allows passage of the piercing needle 186 through a working channel such as indicated by reference numeral 606 of fig4 a 4d with bends and curves as shown in fig5 a the flexible coupling 708 comprises an integral section of flex tubing and as shown in fig5 b the flexible coupling 708 comprises a spliced section of flexible tubing such as silicone rubber or comparable material the drug conduits 282 or 382 of the present invention are manufactured using high quality specialized materials and methods of construction a preferred embodiment is manufactured by putnam precision molding inc of putnam conn the tubing has an inside diameter of about 30 mils and an outside diameter of about 43 mils the co extrusion comprising stainless steel wound nylon tubing provides high columnar strength to prevent against failure of the drug conduit 282 or 382 in high flex situations such as articulation of the distal tip of a catheter device extension of the piercing needle through small radius of curvature bends etc fig5 c is a representative section view of a distal end portion of a drug delivery device of the present invention the tubular wall 720 of the rigid endoscope or elongated catheter shaft coupled to the ddm 100 not shown of the present invention has at least one lumen 722 for the drug conduit such as 282 and 382 above to pass through protected.