Chromatographic study of186Re complexes with various ligands

Abstract

Thin-layer and paper chromatography have been used for the determination of radiochemical yields of lS6Re complexation with three selected ligands methylenediphosphonic acid (MDP), ethylenediamminotetraacetic acid (EDTA), and citrate convenient for the radiopharmaceutical applications. The combination of selected two chromatographic systems has been chosen due to the satisfactory separation of free perrhenate, corresponding complex with lS6Re and reduced hydrolyzed rhenium. Rhenium complexes with studied ligands were prepared by reduction of perrhenate at presence of suitable ligand. Stannous chloride together with ascorbic acid (antioxidant) was used for perrhenate reduction. The effect of pH of reaction mixture, reaction time and concentration of reducing agent on the radiochemical yield of complexation is described and the optimal conditions for synthesis of rhenium complexes with MDP, EDTA and citrate have been found. Under optimal condition the radiochemical yield of complexation lS6Re-MDP, lS6Re-EDTA and lS6Re-citrate reached more than 90%, 80%, and 80%, respectively.

Influence of the rhenium carrier in eluate of Re-188 on its binding with potassium-sodium salt of hydroxyethylidene biphosphonic acid

“…The ratio of Sn 2+: Re 7+ concentrations should not be lower than 10: 1. This ratio is 80 times lower than that recommended in a number of other studies (800: 1) [1][2][3].…”

“…The concentrations of Sn 2+ and of the 188 Re carrier in a reaction mixture influence significantly the radiochemical yield of 188 Re complex. A number of researchers believe that for effective reduction of 188 ReO 4 -the molar ratio of SnCl 2 and NaReO 4 should be 800: 1 [1][2][3]. The presence of an antioxidant (ascorbic or gentisic acid) in the reaction mixture is necessary for increasing the stability of the formed complex [4][5][6].…”

Influence of the rhenium carrier in eluate of Re-188 on its binding with potassium-sodium salt of hydroxyethylidene biphosphonic acid

“…This ratio is 80 times lower than that recommended in a number of other studies (800: 1) [1][2][3]. Concentrations of the reducing agent (Sn 2+ ) and stable rhenium in the 188 Re eluate as the carrier considerably influence the rate of formation and stability of the 188 Re-KNaHEDP complex.…”

Study of perrhenate reduction by capillary electrophoresis

“…The addition of ascorbic acid (as an antioxidant) to the reaction mixture was tested, because it is known, both from the literature and experimental evidence [2][3][4][5][6]14], that ascorbic acid helps to keep stronger reducing environment for dissolved rhenium in lower oxidation state. The addition of ascorbic acid (as an antioxidant) to the reaction mixture was tested, because it is known, both from the literature and experimental evidence [2][3][4][5][6]14], that ascorbic acid helps to keep stronger reducing environment for dissolved rhenium in lower oxidation state.…”

“…The molar excess of stannous chloride over perrhenate in the reaction mixture should be about 800 for obtaining successful reduction of perrhenate with subsequent complexation [1][2][3]. belong to a large group of radiopharmaceuticals applicable in radiotherapy.…”