Biodistribution of Alpha-Fetoprotein-Containing Noncovalent Complex Aimpila with Antitumor Activity

Biodistribution of [¹²⁵I]Aimpila (20 mg/kg) in the tumor and normal tissues, including the mammary gland tissue, after single oral dose was studied in BALB/c nude mice with T47D/ReCAF⁺⁺⁺ human breast tumor sensitive to this drug and in closely related BALB/c nude⁺mice without tumors. The maximum concentration of [¹²⁵I]Aimpila was in fact the same in the tumor and in the mammary gland, while the time course of its accumulation/elimination differed. The time of the maximum accumulation of the drug in the tumor was shorter and its persistence longer than in normal tissue. After 24 h, label concentration in the tumor was 4.5 times higher (p=0.002). Differences in the time course of label accumulation in the tumor were detected. The maximum ratio of tumor/blood concentrations of the preparation was recorded in 1 h after administration. [¹²⁵I]Aimpila and [¹²⁵I]alpha-fetoprotein accumulated in the tumor in comparable concentrations and were eliminated simultaneously at the same rate. The results of comparative analysis of accumulation of the labeled compounds in Aimpila-sensitive T47D/RECAF⁺⁺⁺ tumor from 0.5 to 9.0 h after drug administration could be interpreted as a result of possible receptor-mediated binding of the complex with the tumor at the expense of the alpha-fetoprotein transporting part. Differences in the parameters of [¹²⁵I]Aimpila biodistribution in the tumor and normal mammary tissue indirectly attested to selective antiproliferative activity of the complex.