Determination of adduct forms of antitumor ruthenium(III) complex with cytosolic components by capillary electrophoresis with mass spectrometry

Using capillary electrophoresis with inductively coupled plasma mass spectrometry, the transformation of adduct forms of indazolium trans-[tetrachloridobis(1H-indazole)ruthenate(III)] with apo-transferrin and albumin under the effect of active intracellular reducing agents, glutathione and ascorbic acid, and citric acid as a complexant was studied under conditions simulating a cytosolic environment. These adducts of ruthenium with transport proteins are forms in which the anticancer drug exists after intravenous administration. Two modes of interaction of adducts with glutathione, ascorbic acid, and citric acid were studied: in a capillary using a background electrolyte containing a cytosolic active ingredient and upon incubation of the reaction components in the off-line mode, followed by their separation and determination by capillary electrophoresis. Incubation with intracellular components and separation were carried out in a 10 mM phosphate buffer solution (pH 6.0) containing 4 mM NaCl. The effect 1–10 mM of glutathione, 10 mM of ascorbic acid, and 50 mM of citric acid on the adducts was studied. It is shown that under the selected model conditions, new forms of ruthenium do not emerge.