Hplc system

The beta-emitter ¹⁸⁸Re (half-life, 16.9 h) was produced from beta decay of a parent radionuclide ¹⁸⁸W (half-life 69 days) using a ¹⁸⁸W/¹⁸⁸Re generator (ITG Isotope Technologies Garching GmbH, Germany). After ¹⁸⁸Re was eluted in the form of sodium perrhenate, the antibodies were labeled with ¹⁸⁸Re ‘directly’ through binding of reduced ¹⁸⁸Re to the generated sulfhydryl groups on the antibodies, as described previously [11 (link)]. The radiolabeling yields were measured by instant thin layer chromatography by developing silica gel (SG) 10 cm strips in saline. In this system the ¹⁸⁸Re-labeled antibodies stay at the point of application while free ¹⁸⁸Re moves with the solvent front. The typical radiolabeling yields for both C1P5 and TVG-701Y mAbs were 85%. The radiolabeled mAbs were purified by HPLC using TosoHaas size exclusion column with PBS at 1 ml/min as an eluent using Waters HPLC system equipped with UV and radiation (Bioscan) flow-through detectors. The stability of the ¹⁸⁸Re-radiolabel on the mAbs was determined by incubating the radiolabeled mAbs in mouse serum for 48 h (~3 physical half-lives for ¹⁸⁸Re) at 37°C and analyzing the aliquots on the HPLC size exclusion column described above at 0, 1, 2, 4, 8, 24 and 48 h during the incubation in serum. No loss of ¹⁸⁸Re radiolabel from the mAbs was noted.