SIMPLIFIED KIT FOR INSTANT PREPARATION OF TC-99M HUMAN IMMUNOGLOBULIN-G FOR IMAGING INFLAMMATORY FOCI

A kit consisting of reduced human immunoglobulins G (hIgG), methylene diphosphonate, stannous chloride and ascorbic acid has been developed to instantly produce technetium-labelled hIgG of greater than 97% puri ty and suitable for inflammation foci scintigraphy in patients. The sh elf life of the kit when stored at 4-7 degrees C was at least 3 months . Tc-99m-hIgG prepared from the kit, when incubated at 37 degrees C fo r 24 h in physiological saline and human serum was found to degrade by only 7.8 and 4.3%, respectively, thereby indicating high stability of the labelled product. Competitive RIA data did not exhibit loss of im munoreactivity of the hIgG due to its reduction. Blood clearance of th e radiopharmaceutical in rabbits exhibited a monophasic exponential pa ttern. Biodistribution in mice showed uptake by liver (4.93%), kidneys (3.07%) and intestines (2.12%) at 4 h which was reduced to 1.99, 2.18 and 1.93%, respectively at 24 h. Radiolabelled hIgG prepared from the kit was found to be quite satisfactory for inflammation scintigraphy in human patients.