Preparation and biodistribution of yttrium-90 Lipiodol in rats following hepatic arterial injection

In this study, we labelled Lipiodol with yttrium-90 and analysed the biodistribution in rats after intrahepatic arterial injection. An RP-18 column (E. Merck) was used to separate 90Y from strontium-90. 90Y was retained on the column, which had been pretreated with yttrium-selective extraction reagent, di(2-ethylhexyl) phosphate, while 90Sr was washed out. A hexadentate nitrogen-donor chelating ligand N,N,N',N'-tetrakis(2-benzymidazolylmethyl)-1,2-ethanediamine (EDTB) was synthesized by condensation of 1,2-benzenediamine and ethylene diamine tetra-acetic acid (EDTA). Lipiodol was covalently conjugated with EDTB. The final product was obtained by eluting the retained 90Y from the RP-18 column with EDTB-Lipiodol. Sixteen male rats (Sprague-Dawley) were sacrificed at 1 h, 24 h, 48 h and 72 h (four rats at each time) after injection of approximately 0.1 mCi 90Y-Lipiodol via the hepatic artery. Samples of liver, spleen, muscle, lung, kidney, bone, whole blood and testis were obtained and counted to calculate the tissue concentrations. In addition, labelling efficiency and in vitro stability were determined by ITLC methods. We found that at 1 h after intrahepatic injection, most of the radiotracer was retained in the liver, but it was eliminated gradually over a few days. The radioactivity level in the lung was fair at 1 h and remained at roughly the same level throughout the study. Radioactivity in the kidney and spleen reached a relatively high level at 24 h, but declined rapidly.(ABSTRACT TRUNCATED AT 250 WORDS)