Md 2018 plus

PSMA-617 and RM2 were radiolabeled with ¹¹¹In using an automated synthesizer (GE FastLab, GE Healthcare, GEMS Benelux, Belgium). Briefly, 40 μg of RM2 (Life Molecular Imaging) or PSMA-617 (ABX GmBH) was heated at 90 °C for 5 min using microwaves or ¹¹¹InCl₃ (CURIUM®) and 5 mg of ascorbic acid for RM2. The raw solution was then purified on a C₁₈ cartridge (WAT023501) preconditioned with 1 mL ethanol (Merck®) and 5 mL water (GE®). The final product was then eluted with 1 mL ethanol and formulated in PBS. ¹¹¹In-RM2 and ¹¹¹In-PSMA-617 were checked for radiochemical purity and amount using radio-UV-HPLC (Phenomenex Luna C₁₈; 250 mm × 4.6 mm × 5 μm; 2.5 mL/min, λ = 220 nm; eluent A comprising 0.1% TFA in water, eluent B comprising acetonitrile; gradient 0–10 min, 95% to 5% A). The analytical HPLC system used was a JASCO system with ChromNAV software, a PU-2089 Plus quaternary gradient pump, a MD-2018 Plus photodiode array detector, and Raytest Gabi Star detector.

Radiolabelling experiments were performed on an automated synthetisor (GE FastLab, GE Healthcare, GEMS Benelux, Belgium). Briefly, 40μg of RM2 (Life Molecular Imaging) was heated at 90°C during 5min using micro-waves with 1.1 mL ⁶⁸GaCl₃ (GalliEo generator with nominal activity of 1850 MBq, IRE Elit, Belgium) and 5mg of ascorbic acid. The raw solution was then purified on a C₁₈ cartridge (WAT023501) preconditioned with 1mL ethanol (Merck) and 5 mL water (GE Healthcare). The final product was then eluted with 1 mL ethanol and formulated in PBS. ⁶⁸Ga-RM2 was checked for radiochemical purity using HPLC (Phenomenex Luna C₁₈; 250mm x 4.6mm x 5μm; 2.5 mL/min, λ = 220nm). The analytical HPLC system used was a JASCO system with ChromNAV software, a PU-2089 Plus quaternary gradient pump, a MD-2018 Plus photodiode array detector and Raytest Gabi Star detector. Amount of ⁶⁸Ga-RM2 was determined by UV-HPLC by linear regression of the calibration curve established using the reference compound ^natGa-RM2 (Life Molecular Imaging).