An improved procedure for the efficient labeling of antibodies with Re-188

Monoclonal Antibodies Radiolabeling with Rhenium-188 for Radioimmunotherapy

Rhenium-188, obtained from an alumina-based tungsten-188/rhenium-188 generator, is actually considered a useful candidate for labeling biomolecules such as antibodies, antibody fragments, peptides, and DNAs for radiotherapy. There is a widespread interest in the availability of labeling procedures that allow obtaining ¹⁸⁸Re-labeled radiopharmaceuticals for various therapeutic applications, in particular for the rhenium attachment to tumor-specific monoclonal antibodies (Mo)Abs for immunotherapy. Different approaches have been developed in order to obtain ¹⁸⁸Re-radioimmunoconjugates in high radiochemical purity starting from the generator eluted [¹⁸⁸Re]ReO₄⁻. The aim of this paper is to provide a short overview on ¹⁸⁸Re-labeled (Mo)Abs, focusing in particular on the radiolabeling methods, quality control of radioimmunoconjugates, and their in vitro stability for radioimmunotherapy (RIT), with particular reference to the most important contributions published in literature in this topic.

188Re-labeled hydroxyapatite particles for radiation synovectomy

A new procedure for labeling hydroxyapatite (HA) particles with 188Re for radiation synovectomy is described and standardized. The particles were labeled with 188Re in high yields (99%) in acidic medium. HA particle size remained unaffected by reaction conditions as checked by laser diffraction particle analyzer. 188Re-HA was found to be stable retaining 99% radiochemical purity after 4 days when stored in ascorbic acid solution (10mg/ml, pH 5). Intra-articular injection in rats revealed approximately 98% retention of 188Re-HA in the knee after 48-h pi.