optimized preparation and evaluation of 99mtc-streptomycin

introduction: the endemic occurrence of new strains of tuberculosis around the globe has initiated new research on developing diagnostic radiopharmaceutical based on antibiotics. methods:tc-99m labeled streptomycin was prepared using freshly milked 99mtco4- and various concentrations of streptomycin, stannous chloride at various temperatures in high yield radiochemical purity shown by hplc/rtlc. results:at various phs tested (3-10) the best labeling yield at optimized conditions were at 6-8 range, however ph.7 was considered the best. the radiochemical purity at the best optimized conditions was >95% as shown by rtlc and >97% using hplc (specific activity; 1-3 gbq/mmole). the tracer proved to be stable in the final product and in presence of human serum at 37°c up to 2h. however, biodistribution and high resolution spect studies in wild type mice showed instability of the complex due to high stomach and thyroid activity uptake. conclusion: regardless the reported methods in the literature the direct 99mtc-labeling of aminoglycosides did not proved a suitable tracer.