Photodynamic activity of chloro(5,10,15,20-tetraphenylporphyrinato)indium(III) (InTPP) in vitro was investigated for possible use in photodynamic therapy (PDT). The quantum yield of singlet oxygen generation in DMSO of InTPP (F D = 0.72) was higher than 5,10,15,20-tetraphenylporphyrin (TPP) (F D = 0.52). Binding sites between photosensitizers and bovine serum albumin (BSA) are independent while binding sites with human red blood cells (RBC) are cooperatives, with one and four binding sites per molecule, respectively. Binding constants with BSA are (1.15 ± 0.07) × 10(5) and (2.6 ± 0.1) × 10(4) L mol-1 and with RBC are (2.40 ± 0.05) × 10(7) L mol-1 e (7.2 ± 0.2) × 10(4) L mol-1 for InTPP and Photofrin®, respectively. InTPP was more efficient than Photofrin® in the photooxidation of L-tryptophan(Trp) and BSA when higher concentrations (14 µmol L-1) of photosensitizers were used. InTPP was 1.37-1.5 times more effective in the photooxidation of RBC than Photofrin®. Our results indicate that InTPP should be used in future studies of PDT.
indium(III)-meso-tetraphenylporphyrin; PDT; quantum yield; hemolysis; singlet oxygen
