Sulfonated phthalimidomethyl aluminum phthalocyanine : the effect of hydrophobic substituents on the in vitro phototoxicity of phthalocyanines

摘要

The photocytotoxicity of sulfonated phthalimidomethyl aluminum phthalocyanine, a morehydrophobic photosensitizer as compared to phthalocyanine substituted with sulfonate groups only, wasinvestigated. Inclusion of 1-2 phthalimidomethyl groups into disulfonated aluminum phthalocyanine,resulted in increased partition coefficients between n-octanol and water, and a six-fold increase inboth cellular uptake and photocytotoxicity towards Chinese hamster lung fibroblast cells (line V-79).Reducing the number of phthalimidomethyl groups, or increasing the degree of sulfonation, lead toa decrease in the partition coefficient, cellular uptake, and phototoxicity. The quantum yield of singletoxygen was comparable for all dyes tested in this series, indicating that no significant change in thisphotophysical parameter resulted from phthalimidomethylation. These results suggest that the additionof 1-2 phthalimidomethyl groups to disulfonated aluminum phthalocyanine improves cellular uptake,but, as the relative efficiency of cell killing was not effected, the intracellular distribution on photosensitivemolecules may not be modified.