Stannous Chloride → Ascorbic acid HCl

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Radiolabeling was performed following a literature procedure (Wang et al., Nature Protocols, vol. 1, pp. 1477-1480, 2006). Briefly, 1 mg (75.3 mmol) of compound SRVI34 was dissolved in 1 ml of 0.5 M ammonium acetate buffer at pH 8. Disodium tartarate dihydrate was dissolved in the labelling buffer of 0.5 M ammonium acetate (pH 8) to a concentration of 50 mg/ml. Ascorbic acid-HCl solution was prepared by dissolving ascorbic acid in 10 mM HCl to a concentration of 1.0 mg/ml. A solution of SRVI34 (80 μl) was combined to a solution of 45 μl 0.25 M ammonium acetate, 15 μl tartarate buffer, followed by 5 μl of the freshly prepared 4 mg/ml SnCl2. 2H2O solution in the ascorbate-HCl solution. The final pH will be about 8-8.5. After vortexing, was added 20 mCi of 99mTc-pertechnetate in 200 μl saline and was heated the solution at 90-100° C. for 20 min. Reaction mixture was cooled, diluted 850 μl of water and purified by HPLC using a Phenomenex C18 Luna 10×250 mm2 column on a Waters 600E Delta LC system with a Waters 486 tunable absorbance UV/Vis detector, both controlled by Empower software. HPLC solvent system, flow rate=4 ml/min, a gradient, 0-5 min, 80/20 water/acetonitrile (0.1% TFA in each solvent), 5-25 min 40/60 water/acetonitrile (0.1% TFA in each solvent) and 25-35 min 80/20 (0.1% TFA in each solvent) was used. Two radiolabeled products were found, called as [99mTc]SRVI34A (5.52 mCi) (retention time 17.5 min) and [99mTc]SRVI34B (6 mCi) (retention time 18.9 min) SRVI34A and SRVI32B are diastereomers, syn and anti-isomers with respect to the Tc═O group. Each product was neutralized with 50 μl of 1 M sodium bicarbonate and evaporated to dryness under vacuum. The obtained solid residues was dissolved in 200 μl saline and used for imaging and biodistribution studies.

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