The effect of Glucantime on the labeling of blood constituents with technetium-99m.

PURPOSE The labeling of red blood cells (C) with 99mTc is employed in clinical nuclear medicine for a variety of diagnostic procedures. Drugs can alter this labeling method and modify the disposition of the radiopharmaceuticals. In this paper, the influence of glucantime on the labeling of blood constituents with 9mTc was reported. METHODS Blood was withdrawn from rats and incubated with glucantime. Stannous chloride and 99mTc were added. After centrifugation, plasma (P) and (C) were isolated. Samples of P and C were precipitated with TCA 5%, centrifuged and insoluble (IF) and soluble fractions (SF) separated. The percentages of total activity injected (%ATI) in C, IF-P and IF-C were calculated (p < 0.05). RESULTS The %ATI on C decreased from control to following concentrations of glucantime (6.25%; 12.5%; 25%; 50%; 100%), respectively: 94.06 +/- 1.29 (control) to 77.15 +/- 2.79; to 76.68 +/- 1.88; to 75.15 +/- 2.79; to 72.64 +/- 4.40 and to 63.05 +/- 3.84. On IF-C the %ATI decreased from control to all the concentrations of glucantime (3.125%;6.25%; 12.5%; 25%; 50%; 100%), respectively: 93.34 +/- 1.18 (control) to 78.81 +/- 2.76; to 74.76 +/- 4.82; to 74.02 +/- 5.32; to 64.35 +/- 4.82; to 62.81 +/- 1.97 and to 54.55 +/- 3.58. CONCLUSIONS This effect was probably due to products present in this drug that may complex with ions (Sn(+2) and 99mTcO4) or have a direct or indirect effect on intracellular stannous ion concentration.