The present invention relates to a a nanowire array (15, 16) for electrically-controlled elution of a therapeutic composition (5) comprising a plurality of nanoscopic-sized wires (12, 12'), nanowires, attached to an electrically conducting solid support (7), said nanowires formed from electroactive conjugated polymer (4) containing or doped with said therapeutic composition (5) coated over a plurality of nanoscopic sized electrically conducting protrusions (8). It also relates to a method for preparing a nanowire array and an electrode.