One more PDT application of chlorin e6

In vitro and in ville 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 LD10, 175 mg/kg for LD16, 197 mg/kg for LD50, 220 mg/kg for LD84 (male hybrid mice F1 {CBA x C57Bl/6t}) following 1% aqueous solution i.v. injection. Pharmacokinetics and biodistribution studies have been done using the same mice bearing innoculated 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 (generally by 24 h p.i.) 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% elimination 24 h p.i., and 98% - 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 (SHG YAP:2 laser) being delivered 5-6 h p.i. at different doses (30-210 J/cm(2)). 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.