Rhodium-105 Complexes of Polydentate, Aqueous-Soluble, Phosphine Ligands: New Radiochemical Developments towards Radioimmunotherapy

Abstract

The water-soluble, dithio-bis(hydroxymethyl)phosphine ligands (HOH₂C)₂P(CH₂)_xS(CH₂)₃((CH₂)₄COOH)S(CH₂)_xP(CH₂OH)₂ (X = 2 or 3) were complexed with ¹⁰⁵Rh. ‘The new ¹⁰⁵Rh-complexes were formed in high radiochemical purity by addition of ¹⁰⁵RhCl₃3H₂O to an aqueous solution of the appropriate ligand framework. The new complexes were formed as singular chemical species and did not undergo in vitro decomposition for ≤24 hours as indicated by high performance liquid chromatographic analyses. In vivo bio-distribution analyses of the new complexes indicate that the primary mode of excretion is the renal-urinary pathway. Results of this study suggest the potential development of new radiop-harmaceuticals for the treatment of human metastases via conjugation of the new ¹⁰⁵Rh-complexes to site-specific biomolecular vectors.

Keywords::

• Water-soluble
• Bifunctional Chelating Agents
• (Hydroxymethyl)phosphines