3-[4,5-diethyl-24-[3-[[(2R,3S,5R)-5-(5-fluoro-2,4-dioxopyrimidin-1-yl)-2-(hydroxymethyl)oxolan-3-yl]oxy-hydroxyphosphoryl]oxypropyl]-16,17-bis[2-[2-(2-methoxyethoxy)ethoxy]ethoxy]-10,23-dimethyl-13,20,25,26,27-pentazapentacyclo[20.2.1.13,6.18,11.014,19]heptacosa-1,3(27),4,6,8(26),9,11,13,15,17,19,21,23-tridecaen-9-yl]propyl [(2R,3S,5R)-5-(5-fluoro-2,4-dioxopyrimidin-1-yl)-2-(hydroxymethyl)oxolan-3-yl] hydrogen phosphate;gadolinium(3+)