Evaluation of Di- and Tetra-phenyl-2,3-dihydroxychlorins as Potential Photosensitizers
MacAlpine, J.K. and David Dolphin
J. Porphyrin and Phthalocyanines
A series of β,β-dihydroxychlorins, e.g. I, derived from meso-tetraphenylporphyrins (TPPs) have been synthesized. Their in vitro cytotoxicity has been measured and compared to BPDMA (verteporfin, II). Under the assay conditions BPDMA had an LD50 (LD to kill 50% of cells) value of 0.007 μM (5 ng/mL). The LD50 values for the TPP derivatives varied from 1.7x 10-2 to 9.9 μM depending upon the substituents and their position on the Ph groups. One example of the dihydroxychlorin prepared from unsubstituted 5,15-diphenylporphyrin was examined and this exhibited an LD50 of 2.4 x 10-3 μM!