A simplified kit for instant preparation of technetium-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% purity and suitable for inflammation foci scintigraphy in patients. The shelf life of the kit when stored at 4-7 degrees C was at least 3 months. 99mTc-hIgG prepared from the kit, when incubated at 37 degrees C for 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 immunoreactivity of the hIgG due to its reduction. Blood clearance of the radiopharmaceutical in rabbits exhibited a monophasic exponential pattern. 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.