The effect of electron-accepting substituents in position 3 of the chlorine p6 macrocycle in neutral and carboxyl-containing negatively charged cycloimide derivatives of chlorin p6 (CIC) on the photochemical and biological properties of these photosensitizers was studied. A relationship between the structure and properties of CICs was analyzed on the basis of information on their photoinduced cytotoxicity, efficiency of the generation of reactive oxygen species, photostability, intracellular localization, quantitative parameters of accumulation in cells, and cellular pharmacokinetics. It was shown that these compounds can be used for the development of photosensitizers with intense light absorption at 740 nm, controlled intracellular localization, and a high photodynamic activity toward tumor cells.

Introduction.Bacteriochlorins are the most promising photosensitizers absorbing in the near-infrared spectral region. Their use can enhance the efficiency of photodynamic therapy due to the deeper penetration of radiation into the tumor.Objectiveto conduct a preclinical study of the photoinduced antitumor activity and biodistribution of Bacteriosens.Materials and methods.Bacteriosens is a preparation based on meso-tetra(3-pyridyl)bacteriochlorin absorbing at 747 nm. Photoinduced cytotoxicity was investigated in vitro using human tumor cells: A549, Hep 2, BT-474, MCF-7, SK-BR-3, PC3, and EJ and murine tumor cells: S37, C26, and LLC. In vivo studies were performed in mice with large and small tumors (S37, LLC, and C26).Results.In vitro investigation show that bacteriosens during optical irradiation led to the effective suppression of tumor cell growth in culture (the IC50 value varied from 0,08μМ to 1,21 μМ) and had no toxicity without exposure to light. The effective photodynamic therapy regimen using Bacteriosens in mice with inoculated small and large tumors of different genesis resulted in regression of a primary tumor node on 90–100 % of the animals in the absence of tumor recurrence within 90 days after treatment.Conclusion.Bacteriosens is a promising agent for the photodynamic therapy of small and large tumors; it can be successfully used as an alternative, organ-sparing minimally invasive treatment for malignant tumors, including prostate cancer.

The aim of the paper was to obtain a stable micellar emulsion of potent photosensitizer (PS) –O-propyloxime-N-propoxybacteriopurpurinimide methyl ester absorbing light in long-wave region of the spectrum (λmax= 800±2 нм). Solubilizates of the dye based on different surfactants (Kolliphor ELP, Poloxamer 407, Emuxol 268) were obtained. Taking into account the physical and chemical parameters, the most potent micellar emulsion for injection was selected and characterized. The emulsion based on Kolliphor ELP remains stable for 4 months, with no changes in the fluorescence spectrum and absorption, as well as the particle diameter.