title: A novel [186/188Re]-labelled porphyrin for targeted radiotherapy.
abstract: The concept of labelling a porphyrin, a tumour-avid agent, with a radionuclide to evaluate its potential as a therapeutic modality is reported. A novel water-soluble porphyrin, namely meso-tetrakis[3,4-bis(carboxymethyleneoxy)phenyl]porphyrin, with suitable dicarboxylic acid groups as aromatic substituents in the periphery, was synthesized and characterized. The labelling of this porphyrin with 186/188Re, a beta(-) emitter, was optimized by varying the reaction conditions. The complexation yield was >98% as estimated by paper chromatography in acetone and in saline. The radiochemical purity was found to remain at >98% when stored at 4 degrees C for 24 h. Biodistribution studies in Swiss mice bearing fibrosarcomas showed an uptake of approximately 3.5% per gram of tumour at 30 min post-injection. This uptake in the tumour was retained until 24 h post-injection with major activity showing renal clearance; no significant activity was present in other organs of interest. The tumour/blood and tumour/muscle ratios were observed to be 38 and 5, respectively, at 24 h post-injection, thereby indicating a possible therapeutic potential for tumours.
authors.affiliation: Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai, India.
authors.forename: S
authors.initials: S
authors.lastname: Banerjee
authors.forename: T
authors.initials: T
authors.lastname: Das
authors.forename: G
authors.initials: G
authors.lastname: Samuel
authors.forename: H D
authors.initials: HD
authors.lastname: Sarma
authors.forename: M
authors.initials: M
authors.lastname: Venkatesh
authors.forename: M R
authors.initials: MR
authors.lastname: Pillai
mesh_terms: D000818:Animals; D002854:Chromatography, Paper; D004355:Drug Stability; D005354:Fibrosarcoma / Q000532:radiotherapy; D007553:Isotope Labeling; D051379:Mice; D009368:Neoplasm Transplantation; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D011166:Porphyrins / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D011786:Quality Control; D011868:Radioisotopes; D019275:Radiopharmaceuticals / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D011878:Radiotherapy / Q000379:methods*; D012211:Rhenium; D014018:Tissue Distribution
chemical_list: D009942:Organometallic Compounds; D011166:Porphyrins; D011868:Radioisotopes; D019275:Radiopharmaceuticals; C442104:rhenium meso-tetrakis(3,4-bis(carboxymethyleneoxy)phenyl)porphyrin; D012211:Rhenium