Ru(II) complex mediated PDT for bladder cancer, Biology and dosimetry

Metal-based photo sensitizers are of interest as their absorption and chemical binding properties can be modified via the use of different ligands. Ru
²⁺
based photo sensitizers are known to be effective photodynamic therapy (PDT) agents against bacteria, whereas use for oncological indications in vivo has not been demonstrated with the same level of evidence. We present data showing that premixing the Ru
²⁺
-complex TLD14331,2 ([Ru(II)(4,4'-dimethyl-2,2'-bipyridine(dmb))2(2-(2',2":5",2"'-terthiophene)-imidazo[4,5-f][1,10]phenanthroline)]2+) with transferrin increases the molar extinction coefficient, including longer activation wavelengths, reduces photobleaching rates, reduces the toxicity of the complex and improving overall PDT efficacy demonstrated in Human (HT 1376) and rat (AY27) bladder cancer cells. As the transferrin receptor is upregulated in most malignancies, premixing of the Ru
²⁺
complex with transferrin converts the active pharmaceutical ingredient TLD1433 into a drug of potentially considerable clinical utility.