Radiolabeling of HTK01169 and Analogs

Labellings were performed in Milli-Q water (final volume: 140 μl) to which was added sodium acetate (1 μl, 2.5 M), ascorbic and gentisic acids (10 μl, 50 mM), and 1 nmol of HTK01169, 7 or 8 solubilized in H₂O/ACN (1 : 1). Concentration of the precursors in solution was determined via titration [22 (link),23 (link)]. [¹¹¹In]InCl₃ (20 MBq, 370 MBq ml⁻¹) was added and the mixture was incubated at 90°C for 20 min. Quality control was performed using silica-gel-coated instant thin-layer chromatography (iTLC-SG) eluted with a solution of sodium citrate (0.1 M, pH 5.0). Diethylenetriaminepentaacetic acid (DTPA; 5 μl, 4 mM) was added to complex-free In-111 before injection onto analytical HPLC.