Ad20 hplc system

An ISMATEC peristaltic pump and 11 Elite (Harvard Apparatus, Holliston, MA, USA) syringe pump were used for liquid transfers, an Atomlab 500 dose calibrator and wipe tester (Biodex, Shirley, NY, USA) was used for activity determination, a Bioscan TLC reader Miniscan (Bioscan, Washington, DC, USA) with BioChrome software was used for thin layer chromatogram evaluations, a Thermo Scientific iCAP 6000ICP OES spectrometer was used for impurity determination. The instrumental settings of the manufacturers were as follows: RF generator power 1.15 kW, auxiliary gas flow 0.5 L min⁻¹, nebulizer gas flow 0.40 L min⁻¹, coolant gas flow 12 L min⁻¹. For stability assessment the Shimadzu AD20 HPLC system with UV-Vis (ultraviolet-visible) and radiometric detector GabiStar (Raytest, Straubenhardt, Germany) was used.

Radiolabeling of DOTATATE with scandium was performed by mixing the eluted scandium with 40 μg (ca. 28 nmol, 20 μL of 2 μg μL⁻¹ stock solution in water) DOTATATE in 200 μL 0.2 mol L⁻¹ ammonium acetate buffer (pH 4.0) and equimolar vs. added HCl amount of NaOH then heating for 30 min at 95 °C. Radiochemical yield was determined by thin layer chromatography by developing of 2–5 μL spots on 10 cm silica gel strips in 0.1 mol L⁻¹ citrate buffer pH 4.0 or 1 mol L⁻¹ ammonia acetate:methanol (1:1, v/v). Radioactivity distribution was recorded on a Bioscan TLC reader Miniscan and quantitatively evaluated with BioChrome software. For stability assessment the Shimadzu AD20 HPLC system with UV-Vis and GabiStar radiometric detector was used. The separation was done on a Phenomenex Gemini C18 column (150 mm × 4.0 mm i.d., 5 μm), with 375:115:0.5 (v/v/v) water:acetonitrile:trifluoroacetic acid as a mobile phase and 1.5 mL/min flow rate.