One more PDT application of chlorin e6

In vitro and in vivo biological evaluation of a novel drug substance 'photodithazine' has been performed. In vitro photocytotoxicity (EC50) was 1 (mu) M together with some cytotoxicity. In vivo acute toxicity has been found to be 170 mg/kg for KD10, 175 mg/kg for LD16, 197 mg/kg for LD50, 220 mg/kg for LD84 following 1 percent aqueous solution i.v. injection. Pharmacokinetics and biodistribution studies have been done using the same mice bearing inoculated under the skin of the flanks T36 embryocarcinomas injected i.v. with 40 mg/kg dose of the drug. Maximal tumor and most organs' uptake was attained 1 h.p.i., however, the drug's level in the organs rapidly decreasing to zero with the best tumor/muscle ratios over 10 by 5 h.p.i. 'Photodithazine' has been found to possess rapid clearance from the organism: 94 percent elimination 24 h.p.i. and 98 percent to 48 h.p.i. PDT has been performed in vivo involving 21-23 g A/Snell mice with the same type 0.9-1 g tumors injected 40 mg/kg drug i.p., with 670 nm light being delivered 5-6 h p.i. at different doses. The best irradiation dose has been found to be 170 J/cm2 with a sound necrotic effect and 1-3 week remission. Thus, 'Photodithazine' represents a potent photosensitizer for PDT.