*4.9. Labelling of IP-001 with Indium-111*

A 0.8 mL solution of a 0.05 M HCl and a 60 µL 1.5 M sodium acetate solution (pH 4.66) were placed in a 2 mL microtube. To this mixture, 50 µL of a 1 mg/mL IP-001 water solution was added, followed by 0.2 mL of an indium-111 chloride (60–130 MBq) solution. The reaction was heated at 95 ◦C for 15 min, and aliquots were analyzed by HPLC and radio-TLC to determine the labelling efficiency. When necessary, the labelling mixture was purified by SPE using a light C-18 cartridge. The cartridge was firstly conditioned with 3 mL of EtOH followed by 3 mL of water. Afterwards, sample was loaded and the cartridge was washed with a hydro-alcoholic solution (1.5 mL, water/EtOH 80:20) to remove unlabeled [111In]In3+. The radiotracer <sup>111</sup>[In]In-IP-001 was then eluted with EtOH (0.4 mL) and diluted with water (2 mL). All experiments were performed in triplicate.
