Summary A method is described for the preparation of a freeze‐dried stannous methylene diphosphonate kit* (Sn‐MDP) suitable for use in bone scanning after complexing with 99mTc. Several combinations of the reagents were used, and these resulted in different levels of bone and soft tissue localization. Two of such combinations produced a kit which localized predominantly in bone, and of these only one showed consistent batch to batch reproducibility. The biological distribution of the labelled compound has been tested in animals, and the results obtained at 2 h post‐injection are presented. The shelf‐life has been found to be in excess of 3 months, and quality control using thin layer chromatography has shown a labelling yield >95%.

Pyridoxylideneglutamate has been prepared in kit form for complexing with technetium-99m and used as a hepatobiliary scanning agent. The active complex was formed as a result of autoclaving the mixture for 30 mins at a temperature of 121°C. A series of sequential studies in rabbits revealed rapid clearance from the blood by the liver followed by a high excretion into the gall-bladder and finally clearing via the bile duct into the small intestine. The optimum period for visualization of the gall-bladder was found to be in the region of I0 -15 mins.The tissue distribution of this agent has been studied in mice, and results obtained at 5 , 10, 15,30 and 60 mins following injection are presented.