title: Molecular weights of technetium hydroxyethylidene diphosphonate complexes.
abstract: The results of recycle size-exclusion and anion-exchange chromatography are combined to determine molecular weights and radii of gyration for selected components of a carrier-added technetium hydroxyethylidene diphosphonate radiopharmaceutical bone-imaging preparation. Samples evaluated by size-exclusion are selected from fractions collected as the preparation elutes from the anion-exchange column. Polyethylene glycol and polyphosphate molecular weight standards are used, in conjunction with the universal calibration method, to determine Mark-Houwink constants and to estimate molecular weights for the complexes. The results of this study support a spherical shape model for the collection of technetium complexes. Given the combined knowledge of molecular weights, charges, technetium concentration dependencies, and mass spectral data, several formula assignments are proposed, including TcO(OH)L-1, Tc2O(OH)6L-3, Tc2O(OH)2L3(-6), Tc3O2(OH)3L2(-5), Tc3O2(OH)3L3(-7), Tc2O2(OH)4(HL)3(-7) and Tc2O2(OH)4(H2L)4(-8).
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D012968:Etidronic Acid; D008970:Molecular Weight; D015609:Organotechnetium Compounds; D013667:Technetium
chemical_list: D015609:Organotechnetium Compounds; C019561:technetium Tc 99m etidronate; D013667:Technetium; D012968:Etidronic Acid