Selective biodistribution (targeted to liver only, without adverse reactions in other organs) of a model cytostatic agent, ¹³¹I-radiolabelled docetaxel, was studied with lipiodol (20% emulsion of lipophilic x-ray contrast, ethiodized poppy seed oil) as an excipient. ¹³¹I-lipiodol alone was compared with a mixture of ¹³¹I-alocetaxel + non-radiolabelled lipiodol. Emulsions were administered to rabbits in ketamine-xylasine anaesthesia by slow infusion either to v. portae (after laparotomy) or to v. jugularis. Time-dependence of biodistribution was qualitatively estimated by 12-min whole body scintigraphy with gammacamera, whereas samples of blood and organs (taken in the pharmacokinetic "steady-state"), measured by gammacounter, yielded quantitative data of radioactivity in individual body compartments. Preferential accumulation was observed for both emulsions: ¹³¹I-lipiodol alone, intraportally, showed initial radioactivity localization in the liver and a slightly delayed pulmonary distribution, whereas the ¹³¹I-docetaxel-lipiodol mixture, after the initial capture in liver and lungs, showed some radioactivity spreading to other body areas incl. head and bile. For intrajugulary administration of lipiodol alone, localization was observed in the order: pulmonary area, upper abdomen (liver, spleen); for the ¹³¹I-docetaxel-lipiodol mixture, capture proceeds through lungs and abdomen (liver, spleen, kidneys), too, spreading further to head and other organs.

Keywords: Toxicology; cytostatic agent