99mTc-gentamicin: chemical and biological evaluation.

99mTc-Gentamicin complex, a new agent for renal studies, is prepared by the reduction of pertechnetate by stannous chloride. Organ distribution in rats and paper chromatography with Whatman 3MM paper [developed in n-butanol, acetic acid, and water (4:1:1)] were favored as analytical tools for determination of labeling parameters of 99mTc-Gentamicin. A higher concentration of stannous ion is responsible for the formation of insoluble technetium species which concentrate in the liver. The mean kidney: liver ratio of 10.4:1 was obtained 1 h after injection. This confirms that scintigraphic delineation of kidneys is highly satisfactory.