| abstract |
Proteins are radiolabeled with technetium-99m in a reducing environment comprising buffered stannous chloride wherein the tin utilized to form the stannous chloride is non-oxidized, the buffered stannous chloride is purged of oxygen and the buffer comprises an alkali metal biphthalate and an alkali metal tartrate. Proteins which have been preincubated with tin are radiolabeled with technetium-99m to form a strongly bonded, non-exchangeable radiolabeled tracer substance. The radiolabeling can be accomplished immediately after pretinning, or the pretinned proteins can be freeze-dried and the radiolabeling accomplished at some time in the future when the pretinned proteins are resolubilized in a saline solution of sodium pertechnetate - TC-99m. Pretinning can be accomplished in a reducing environment comprising stannous chloride buffered with an alkali metal biphthalate and an alkali metal tartrate, this solution having been purged of oxygen to assure that the stannous chloride is non-oxidized. When the pretinning proteins are freeze-dried, they can be utilized to prepare instant TC-99m labeling kits for use as radiopharmaceuticals. |