Investigation of Palladium(II) Binding with Chlorin e6 and Evaluation of Safety for Use in an “In Vitro” Model

The possibility of synthesis a water-soluble palladium complex with Chlorin e6 as part of the Photoditazine drug has been investigated. Based on data from electronic absorption and luminescence spectroscopy, it was concluded that a complex of palladium and Chlorin e6, with palladium located in a tetrapyrrole ring, was formed. In particular, it was found that the luminescence intensity and the wavelength of the Chlorin e6 band increased in solutions containing Chlorin e6 and palladium. Mass spectrometry analysis determined that the complex was [Pd : Chlorin e6]2–. The complex of Chlorin e6 with palladium in a 0.5 : 1 molar ratio was identified as most promising for further research due to its rapid accumulation in tumor cells, low toxicity and minimal impact on cellular membrane integrity.