JOURNAL OF NUCLEAR MEDICLNE 7:643-646, 1966 The Removal and Control of Iodide-131 Contamination2 in Sodium O-Iodo1!1 Hippurate

With free iodide-131 present in solutions of sodium o-iodo131 hippurate (radio Hippuran, OI131HA) the results are inconsistent when the material is used in renal clearance tests(l). A method was reported earlier for the removal of this contamination, involving the treatment of the OI131HA solutions with freshly precipitated silver-chloride ( 1). Apparently, self-irradiation in OI131HA solutions causes the release of iodide-131 (1,2). The resulting presence of iodide-131 may in turn give rise to further contamination with radioiodinated organic materials (3,4). Even in solutions of OI131HA which have been purified by the silver-chloride treatment, iodide-131 contamination will again increase, especially if the specific activity is high. A material was sought which could be placed in contact with the stored solutions of radioiodinated pharmaceuticals and would remove the contaminating radioiodide as it formed. Volk Radiochemical Company supplied us with silver-chloride coated Beri porcelain saddles for evaluation and some similar saddles were prepared in this laboratory. ( Beri saddles are normally used as fractionating column packing.) The silver chloride acts as an ion-exchange medium, exchanging chloride ions for iodide ions. The Beri saddle merely acts as an inert support for the silver-chloride to prevent more than a negligible contamination of the phar maceutical with silver-chloride. Since a large area of silver-chloride must be ex posed to the solution for effectiveness, and since Beri saddles are essentiall