Table 5 Radiolabeling studies performed on scandium radionuclides
Type of vector | RN used | Buffer, pH, T°, time conditions | Quality Control / RCY | Molar activity | Post-radiolabeling purification | Reference |
|---|---|---|---|---|---|---|
DOTA | 44Sc | 0.2 M ammonium acetate pH = 4.8 80 °C 30 min | iTLC with H2O | 51 GBq/μmol competitive metal impurities of 28 μM (mostly Fe) | Not indicated | (Severin et al. 2012) |
DTPA HEBD BAPTA EGTA TTHA DFO DOTA | 47Sc | 20 mM acetate buffer pH = 6.0 RT | iTLC with NH3/H2O (1/25) DTPA RCY = 38.8–100% EGTA RCY = 97.2–100% DOTA RCY = 79.4–97.7% | Estimation 0.017 MBq/nmol | Not performed | |
picagaDUPA | 44Sc | 0.25 M NaOAc buffer solution pH = 4 at 25 or 80 °C. | TLC with 50 mM EDTA RCY = 83% at 25 °C RCY = 96% at 80 °C | Calculated from (Polosak et al. 2013) 0.03 MBq/nmol | Not performed | (Vaughn et al. 2020a) |
AAZTA-c(RGDfK) | 44Sc | 0.25 M ammonium acetate pH = 4 room temperature 5 min | RCY = 99% | 0.36 GBq/μmol | (Nagy et al. 2017a; Vaughn et al. 2020a; Kostelnik and Orvig 2019) | |
Propargyl-DOTA | 44Sc | 95 °C for 30 min | HPLC Phenomenex Synergi, 4 μ, Hydro-RP, 80 Å a gradient with the eluents acetonitrile (A) and H2O (B), both containing 0.1% trifluoroacetic acid and a flow rate of 1.0 mL/min. RCY = 69–92% | Other metals: Zn (5.4 ± 4.5 ppm), Fe (1.1 ± 0.7 ppm), Pb (0.38 ± 0.13 ppm) and Al (0.18 ± 0.14 ppm) | Not performed | (Hoehr et al. 2014) |
DOTA - puromycin | 44Sc | 0.25 M ammonium acetate pH =4 95 °C 20 min | iTLC Elution with n-propanol/ NH4OH/H2O (55:35:10) RCY = 78% | 1.5 GBq/μmol | HPLC - C-18 cartridge (Strata-X Polymeric Sorbet 60 mg/mL Phenomenex) Elution with ethanol Radiochemical purity ≥97% | (Eigner et al. 2013) |
DOTA-Folate | 44Sc | 1 M ammonium acetate pH 3.5–4 95 °C 10 min | HPLC - C-18 column (Xterra MS C18, Waters). Mobile phase: Milli Q water with 0.1% trifluoracetic acid (A) and methanol (B) with a linear gradient from 95% A and 5% B to 20% A and 80% B over 25 min with a flow rate of 1 mL/min RCY ≥ 96% | ≥ 5.2 MBq/nmol, representing a 44Sc–to–ligand molar ratio of 1:5600 | Not indicated | (Muller et al. 2018) |
47Sc | CH3COONH4/HCl pH 4.5 95 °C 10 min | HPLC as above RCY ≥ 96% | no radionuclidic impurities were detectable 13 MBq/nmol | Not indicated | (Muller et al. 2014) | |
PSMA-617 | 44Sc | 0.25 M ammonium acetate pH = 4 95 °C 25 min | iTLC 1:1 v/v 1 M ammonium acetate / methanol RCY = 74%- 98% | 1.82–6.69 MBq/nmol | HPLC - C-18 cartridge (Sep-Pak C18 Plus Short Waters) - after a pre-conditioning with 4 mL of ethanol and 10 mL of water. Elution with pure ethanol. | (Eppard 2018) |
DOTANOC | 44Sc | 0.2 M sodium acetate buffer pH 4 85 °C 15 min | HPLC C-18 (XterraTM MS column 95% MilliQ water with 0.1% trifluoracetic acid (A) and 5% acetonitrile (B) over a 20-min period at a flow rate of 1 mL/min RCY ≥ 98% | Not indicated | (van der Meulen et al. 2015) | |
47Sc | 0.5 M sodium acetate pH 4.5 95 °C 15 min | HPLC C-18 (XterraTM MS column 95% MilliQ water with 0.1% trifluoracetic acid (A) and 5% acetonitrile (B) over a 20-min period at a flow rate of 1 mL/min RCY ≥ 96% | 10–25 MBq/nmol | Not indicated | (Domnanich et al. 2017a) | |
DOTATOC | 44Sc | 0.8 M ammonium acetate pH = 5 91 °C 30 min | iTLC RCY = 99% | 1.4 MBq/μg | Not indicated | (Singh et al. 2017) |
44Sc | 0.25 M ammonium acetate pH = 4 95 °C 30 min | iTLC a) 0.1 M sodium citrate pH 4.0 (b) mixture of 5% NaCl with MeOH (3:1) (c) mixture of 5% NaCl with MeOH and 25% NH3 (3:1:1) RCY ≥ 98% | 9 GBq/μmol | Performed on RP C-18 mini-cartridge Strata-X Elution with pure ethanol | (Kerdjoudj et al. 2016) | |
DOTATATE | 44m/44Sc | 0.1 M ammonium acetate pH 4–6 70 °C 20 min | TLC 25% aq. NH3/H2O/MeOH, 2/1/1 (v/v) RCY ≥ 95% | 8 MBq/nmol radionuclidic purity = 99% | Not performed | (Huclier-Markai et al. 2018; Alliot et al. 2015a; Alliot et al. 2015b) |
43Sc | ammonium acetate pH = 5 90 °C 35 min | TLC 0.1 M sodium citrate (pH = 5.0) RCY = 98.3% | Not indicated | Not performed | (Szkliniarz et al. 2016) | |
CHX-A”-DTPA-Fab fragment of Cetuximab | 44Sc | 0.5 M sodium acetate buffer pH 6.5 adjusted to ∼4.5 room temperature (25 °C) 30 min | TLC 50% aqueous acetonitrile | 63 GBq/μmol | PD-10 columns PBS as the mobile phase | (Chakravarty et al. 2014) |
DOTA -ZHER2–2891 | 44Sc | RCY = 98% | 7.8GBq/μmol | (Honarvar et al. 2017) |