Stable, concentrated radionuclide complex solutions

A process for manufacturing a pharmaceutical aqueous solution, the process comprising diluting an aqueous complex solution with an aqueous dilution solution to form the pharmaceutical aqueous solution, wherein

• the aqueous complex solution comprises:
• (a) a complex comprising (ai) the radionuclide 177Lu (Lutetium-177) and (aii) a somatostatin receptor binding peptide linked to the chelating agent DOTA, and
• (b) at least one stabilizer(s) against radiolytic degradation selected from gentisic acid or a salt thereof, ascorbic acid or a salt thereof, methionine, histidine, melatonine, and Se-methionine that is/are present in an amount to result in a concentration of 0.2 to 5 mg/mL in the pharmaceutical aqueous solution;
• the aqueous dilution solution comprises at least one stabilizer(s) against radiolytic degradation selected from gentisic acid or a salt thereof, ascorbic acid or a salt thereof, methionine, histidine, melatonine, and Se-methionine that is/are present in an amount to result in a total concentration of 0.5 to 10 mg/ml in the pharmaceutical aqueous solution;
• and
• the radionuclide is present in the pharmaceutical aqueous solution in a concentration that provides a volumetric radioactivity of 250 to 500 MBq/mL.