Comparison of photophysical properties of two zinc (II) phthalocyanines in dimethylformamide or into liposomes

MARIANA MIRETTI; TEMPESTI, T. C; CESAR G. PRUCCA; M. TERESA BAUMGARTNER

Carlos Paz, Córdoba

Encuentro; XIII ELAFOT; 2017

XIII ELAFOT

Photodynamic therapy (PDT) utilizes light in combination with a photosensitizing agent to induce several phototoxic reactions. Both components are innocuous if they act separately but in combination, are able to induce injury and cellular death [1]. Photodynamic reaction involves a light absorption by a photosensitizer to excite the molecule to the excited singlet state. This excited state undergoes intersystem crossing to the long-lived triplet state, which can react with molecular oxygen inducing reactive species such as singlet oxygen, superoxide, and radicals. These reactive species can oxidize the surrounding bioorganic molecules leading to cell death [2].Phthalocyanines (Pcs), second generation photosensitizers, are characterized with far red wavelength absorption (>670 nm), long triplet life time (~1 ms), and high quantum yields of singlet oxygen generation (>0.2) [3]. Pcs have been used as a treatment for a variety of cancers and non oncological applications, such as actinic keratosis and mycosis fungoides.Due to hydrophobic character of Pcs, intravenous treatment is greatly hampered. Liposomal preparations are currently used as an effective delivery system in experimental studies and clinical trials [4].