CHLORIN-E(6) PHARMACOKINETICS, TOXICITY AND ANTITUMOR EFFICIENCY IN PHOTODYNAMIC TREATMENT OF WISTAR RATS WITH SARCOMA-M-1

Pharmacokinetics, toxicity and antitumour effect of chlorin e6 after l ight irradiation were studied. The concentration of chlorin e6 in the blood, liver, kidney, spleen and sarcoma M-1 of the rats was determine d by the fluorescence method 3, 6, 12, 18, 24, 48 and 72 hours after t he agent i. p. injection in a dose of 10 mg/kg. The acute toxicity of chlorin e6 was studied on C3H mice and Wistar rats without tumours. Th e antitumour effect of photodynamic treatment with chlorin e6 was stud ied on transplantable sarcoma M-1 of rats. The tumours were irradiated by krypton ion laser light (647 and 676 nm, 22.5 = 180 J/cm2) after i . v injection of chlorin e6 (1-10 mg/kg). The time interval between th e photosensitizer injection and photoradiation varied from 15 min to 7 2 hours. Tumour growth inhibition coefficient (TGIC), tumour regressio n rate and cure of animals were used as antitumour criteria of the pho todynamic treatment. The results have shown that chlorin e6 LD50 value in C3H mice was 189.4+/-9.4 mg/kg, in Wistar rats it was 113.4+/-17.7 mg/kg 14 days after the agent i. p. injection. It was found that the antitumour effect of the photodynamic therapy logarithmically depended on the light energy exposure, and chlorin e6 dose causing 50 % cure o f sarcoma M-1 in rats was 10 mg/kg, i. e. about 1/10 part of LD50 valu e.