Properties of the Novel Photosensitizer β,β,β′,β′-Tetramethyltribenzotetraazachlorin

The abilities of solubilizers Cremophor EL, Tween 80, Emuxol 3, and Pluronic F-68 to deliver the novel promising photosensitizer β,β,β′,β′-tetramethyltribenzotetraazachlorin (H2TBTAC) into A549 human lung adenocarcinoma cells in vitro were compared. It was found that the number of H2TBTAC monomers in the solubilizer solutions correlated with the amount of fluorescent monomer accumulated in the cells. The H2TBTAC monomer showed significantly higher ability to generate singlet oxygen than H2TBTAC aggregates. It was established that Cremophor EL provided the maximum amount of H2TBTAC monomers in solution and the best stability during storage of the composition. Cremophor EL improved the accumulation of H2TBTAC monomer in A549 cell cytoplasm (reaching saturation after incubation for 2 h) and gave the maximum H2TBTAC accumulation coefficient (0.7 ± 0.1). Experiments in vivo showed therapeutically significant antineoplastic activity for photodynamic therapy with H2TBTAC stabilized in Cremophor EL solution (10%).