Photophysical and Photobiological Studies of a Silicon Tribenzonaphthoporphyrazinato Incorporated into Liposomes for Photodynamic Therapy Use

Nanostructured drug delivery systems (NDDS), such as liposomes, represent a growing area in biomedical research. These microheterogeneous media can be used in many biological systems to provide appropriate drug levels with a specific biodistribution. The photophysical properties of a silicon derivative of tribenzonaphthoporphyrazinato (Si-tri-PcNc) incorporated into liposome were studied by steady-state techniques, time-resolved fluorescence and laser flash photolysis. All the spectroscopy measurements performed allowed us to conclude that Si-tri-PcNc in liposome is a promising NDDS for PDT. The in vitro experiments with liposomal NDDS showed that the system is not cytotoxic in darkness, but exhibits a substantial phototoxicity at 1 μM of photosensitizer concentration and 10.0 J/cm² of light. These conditions are sufficient to kill about 80% of the cells.