A novel lutetium(III) acetate phthalocyanine directly substituted with N,N?-dimethylaminophenyl groups via C-C bonds and its water-soluble derivative for photodynamic therapy

Abstract

In this study, the novel 4-(N,N'-dimethylamino)phenyl substituted lutetium(III) acetate phthalocyanine (2) and its quaternized derivative (3) were synthesized via a Suzuki-Miyaura coupling reaction between tetrakis(iodo) lutetium(III)acetate phthalocyanine (1) and 4-(N,N-dimethylamino)phenylboronic acid, and subsequent quaternization using dimethyl sulfate, respectively. The obtained phthalocyanine 3 exhibited excellent solubility in water which is important for photodynamic therapy applications. Photophysical properties such as fluorescence quantum yield and fluorescence lifetime, and photochemical properties such as singlet oxygen, generation and photostability were investigated to determine their suitability for photodynamic therapy. The lutetium(III) phthalocyanines, especially quaternized derivative 3, showed promising properties as potential photosensitizers for the treatment of cancer, producing higher singlet oxygen (Phi(Delta) = 0.59) than,motexafin lutetium (Phi(Delta) = 0.31) which is a clinically used lutetium texaphyrin photosensitizer. (C) 2017 Elsevier Ltd. All rights reserved.