Paper chromatographic and paper elettrophoretic study of the solution chemistry of Tc-99m-methylendiphosphonate and of Tc-99m-dimercaptosuccinate for improving the tumour-affinity of Tc-99m during scintigraphic imaging of cancer.
In order to find the conditions under which Tc-99m-methylenediphosphonate (Tc-99m-MDP) and Tc-99m(V)-dimercaptosuccinate (Tc-99m(V)-DMSA) may become tumour-seeking agents, leaving healthy organs free from the radionuclide uptake, the solution chemistry of these radiopharmaceuticals was studied by paper chromatography and paper electrophoresis in distilled water, in physiological saline, in NAHCO3, and ascorbic acid solutions. Both radiopharmaceuticals are anionic in the radiopharmaceutical solution but get easily hydrolysed to form cationic Tc-99m species which concentrates in healthy bone and in some bone metastases. Tc-99m (V)-DMSA being more stable remains long in the blood pool giving undesirable presence of the radionuclide in lung, heart and kidneys, in addition to its reduced uptake in bone metastases and in some primaries. We are trying to eliminate these drawbacks of healthy organ uptake of Tc-99-m(V)-DMSA not only to get a clean scintigraphic image of the tumour with this radiopharmaceutical but to extend its formulation, thus obtained, to prepare radiopharmaceutical with Re-188, which is the higher homologue of Tc-99m, for systemic therapy of cancer. Essentially similar solution chemistry of both radiopharmaceuticals suggests that like Tc-99m-MDP, technetium-99m-dimercaptosuccinate is also a complex of tetravalent Tc-99m and not of pentavalent Tc-99m as so far supposed to be.
Shukla
Shyama Kant
SK
Servizio di Medicina Nucleare, Ospedale S Eugenio, Piazzale Umanesimo 10, 00144 Roma, Italy. Francesco.petrucci@iss.it
Atzei
Giampiero
G
Sedda
Antioco Franco
AF
Rossi
Gabriele
G
Cipriani
Cesidio
C
D002854:Chromatography, Paper; D004590:Electrophoresis, Paper; D006801:Humans; D009369:Neoplasms / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000032:analysis* / Q000493:pharmacokinetics; D019783:Technetium Tc 99m Dimercaptosuccinic Acid / Q000032:analysis* / Q000493:pharmacokinetics; D013669:Technetium Tc 99m Medronate / Q000032:analysis* / Q000493:pharmacokinetics; D014018:Tissue Distribution
D019275:Radiopharmaceuticals; D019783:Technetium Tc 99m Dimercaptosuccinic Acid; D013669:Technetium Tc 99m Medronate