Phototoxicity of the chemotherapeutic agents hematoporphyrin D, meso-tetra(p-sulfophenyl)porphine and zinc-tetra(p-sulfophenyl)porphine.

Interest in natural and synthetic porphyrins as tumor-localizing agents, tumor-photoinactivating agents and anti-trypanosomal drugs prompted a laboratory evaluation of the phototoxic potency of these compounds. At UV wavelengths greater than 3200A three porphyrin compounds were significantly more phototoxic than the positive control, 6,8-dichloro-2-phenyl-alpha-2-piperidyl-4-quinoline methanol. Phototoxicity was seen after intraperitoneal administration but not after oral administration. Minimum effective phototoxic doses of Hematoporphyrin D were < 2.40 mg; TPPS < 1.25 mg/kg, and ZnTPPS < 1.24 mg/kg. Hematoporphyrin D produced toxic deaths at doses of 37.5-150 mg/kg.