FASTER AND EASIER RADIOCHEMICAL PURITY TESTING FOR [I-125] SODIUM IOTHALAMATE

A previous method for determination of the radiochemical purity (RCP) value of [I-125]sodium iothalamate uses two paper strips and solvents (total developing time is similar to 2.5 h). To simplify and shorten t he RCP testing procedure, our laboratory has developed a single-strip chromatography method that not only distributes free I-125 and [I-125] sodium iothalamate to different relative front (R-f) locations, but is also faster and easier to perform. RCP of [I-125]sodium iothalamate w as determined with the we of a 10-cm instant thin-layer chromatography strip impregnated with polysilicic acid gel (ITLC-SA) as the solid ph ase, and a mobile phase of 2-butanol:acetic acid:water (140:2.5:70, v/ v). By using autoradiography and counting the strip segments in a gamm a counter, our results indicated that free I-125 migrated to R-f = 0.8 9-1.00 while the [I-125]sodium iothalamate moved to R-f = 0.44-0.67. T he total developing time for the single-strip ITLC-SA system was simil ar to 1 h. (C) 1997 Elsevier Science Inc.