N-{(3r,6s,9s,12r)-6-Ethyl-12-Methyl-9-[3-(N'-Methylcarbamimidamido)propyl]-2,5,8,11-Tetraoxo-3-Phenyl-1,4,7,10-Tetraazacyclotetradecan-12-Yl}-2-Methylpropanamide