Inhibition of tumor growth with ultralow doses of doxorubicin under experimental conditions.

Antitumor activity of ultralow doses of cytostatic doxorubicin was studied on BDF1 mice with Lewis lung carcinoma. The preparation was injected intraperitoneally in single doses of 10(-5), 10(-10), 10(-15), and 10(-20) M on the next day after tumor inoculation. The effect of ultralow doses was compared with that of a standard therapeutic dose of doxorubicin (8 mg/kg, 1.4 x 10(-3) M). Doxorubicin in ultralow doses produced an antitumor effect comparable with that induced by the preparation in standard doses. On day 12 after administration of doxorubicin in ultralow and standard doses, tumor size in mice did not exceed 20% of the control level.