Automated, cassette-based isolation and formulation of high-purity [(61)Cu]CuCl(2) from solid Ni targets

BACKGROUND: A need for improved, cassette-based automation of (61)Cu separation from irradiated Ni targets was identified given the growing interest in theranostics, and generally lengthy separation chemistries for (64)Cu/(64)Ni, upon which (61)Cu chemistry is often based. METHODS: A method for separating (61)Cu from irradiated (nat)Ni targets was therefore developed, with provision for target recycling. Following deuteron irradiation, electroplated (nat)Ni targets were remotely transferred from the cyclotron and dissolved in acid. The dissolved target solution was then transferred to an automated FASTlab chemistry module, where sequential TBP and TK201 (Triskem) resins isolated the [(61)Cu]CuCl(2), removed Ni, Co, and Fe, and concentrated the product into a formulation suitable for anticipated radiolabelling reactions. RESULTS: (61)Cu saturation yields of 190 ± 33 MBq/μA from energetically thick (nat)Ni targets were measured. The average, decay-corrected, activity-based dissolution efficiency was 97.5 ± 1.4% with an average radiochemical yield of 90.4 ± 3.2% (N = 5). The isolated activity was collected approximately 65 min post end of bombardment in ~ 2 mL of 0.06 M HCl (HCl concentration was verified by titration). Quality control of the isolated [(61)Cu]CuCl(2) (N = 5) measured (58)Co content of (8.3 ± 0.6) × 10(− 5)% vs. (61)Cu by activity, Ni separation factors ≥ (2.2 ± 1.8) × 10(6), EoB molar activities 85 ± 23 GBq/μmol and NOTA-based EoB apparent molar activities of 31 ± 8 MBq/nmol and 201 MBq/nmol for the 30 min and 3.3 h (N = 1) irradiations, respectively. CONCLUSION: High purity (61)Cu was produced with the developed automated method using a single-use, cassette-based approach. It was also applicable for (64)Cu, as demonstrated with a single proof-of-concept (64)Ni target production run.