名称:
Water-Soluble, Core-Modified Porphyrins as Novel, Longer-Wavelength-Absorbing Sensitizers for Photodynamic Therapy
摘要:
Water-soluble, core-modified 5,10,15,20-tetrakis(4-sulfonatophenyl)-21,23-dithiaporphyrin (1) and 5,10,15,20-tetrakis(4-sulfonatophenyl)-21,23-diselenaporphyrin (2) were prepared as the tetrasodium salts by the sulfonation of 5,10,15,20-tetraphenyl-21,23-dithiaporphyrin (3) and -21,23-diselenaporphyrin (4), respectively, with sulfuric acid. Compounds 3 and 4 were prepared by the condensation of pyrrole with either 2,5-bis(phenylhydroxymethyl)thiophene (5) or 2,5-bis(phenylhydroxymethyl)selenophene (6) in propionic acid. The addition of benzaldehyde to 2,5-dilithiothiophene or 2,5-dilithioselenophene gives 5 or 6, respectively, as a nearly equimolar mixture of meso- and d,l-diastereomers. Careful crystallization of 5 gives a single diastereomer by removing the crystalline product from the equilibrating mixture of diastereomers in solution, Photodynamic therapy (PDT) with 1 has an LD50 of less than 25 mu g/mL against Colo-26 cells in culture and exhibits a lethal dose for 90% or more at concentrations greater than 50 mu g/mL. In contrast, PDT with 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS4) requires concentrations of greater than 100 mu g/mL to achieve LD50 Neither 1 nor TPPS4 shows significant photoactivity against the murine T-cell line, MOLT-4, above the dark toxicity. Sensitizer 1 shows no toxicity or side effects in BALB/c mice observed for 30 days following a single intravenous injection of 10 mg (9.1 mu mol)/kg. Distribution studies show that sensitizer 1 accumulates in the tumors of BALB/c mice bearing Cole-26 or EMT-6 tumors with sensitizer concentration roughly doubling as the dosage of 1 increased from 5 to 10 mg/kg. In vivo studies show that PDT with sensitizer 1 at both 3.25 and 10 mg/kg with 135 cm(-2) of 694-nm light is effective against Cola-26 tumors in BALB/c mice.