title: [125I/127I/131I]Iodorhodamine: synthesis, cellular localization, and biodistribution in athymic mice bearing human tumor xenografts and comparison with [99mTc]hexakis(2-methoxyisobutylisonitrile).
abstract: The synthesis of halogenated rhodamine (Rh) derivatives was carried out by controlling the stoichiometry of the halogenating agents, bromine and iodine monochloride. In the no-carrier-added synthesis of radioiodinated rhodamine 123, direct labeling of rhodamine 123 (Rh 123) with Na125I/Na131I required the presence of the oxidant peracetic acid. 125I/131I-Rh 123 was synthesized in modest yields (40-45%). HPLC purification separated Rh 123 from its mono- and diiodo derivatives. Monohalogenation of Rh 123 did not alter the compound's ability to permeate viable cells and localize in mitochondria. 125I/131I-Rh 123 was stable in serum in vitro but rapidly metabolized after intravenous injection into mice. Consequently, scintigraphy and biodistribution data reveal poor targeting of subcutaneously growing human tumor xenografts. The results are compared to those obtained following the administration of [99mTc]hexakis(2-methoxyisobutylisonitrile) which also did not image human tumor xenografts in nude mice.
authors.affiliation: Department of Radiology (Nuclear Medicine), Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: R S
authors.initials: RS
authors.lastname: Harapanhalli
authors.forename: A M
authors.initials: AM
authors.lastname: Roy
authors.forename: S J
authors.initials: SJ
authors.lastname: Adelstein
authors.forename: A I
authors.initials: AI
authors.lastname: Kassis
mesh_terms: D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007553:Isotope Labeling; D007624:KB Cells; D051379:Mice; D008819:Mice, Nude; D008856:Microscopy, Fluorescence; D009303:Nasopharyngeal Neoplasms / Q000000981:diagnostic imaging; D009368:Neoplasm Transplantation; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000138:chemical synthesis* / Q000493:pharmacokinetics*; D012235:Rhodamines / Q000138:chemical synthesis / Q000493:pharmacokinetics; D017256:Technetium Tc 99m Sestamibi / Q000493:pharmacokinetics*; D014018:Tissue Distribution; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured
chemical_list: D019275:Radiopharmaceuticals; D012235:Rhodamines; D017256:Technetium Tc 99m Sestamibi