Photobleaching characteristics of α-(8-quinolinoxy) zinc phthalocyanine, a new type of amphipathic complex

Abstract

The aim of this study was to reveal the photobleaching characteristics of α-(8-quinolinoxy) zinc phthalocyanine (ZnPc-F7), a new type of amphiphilic complex. Normal saline (NS), pure Roswell Park Memorial Institute (RPMI)-1640 medium (1640), RPMI-1640 medium containing 10% fetal calf serum, and cell suspension were used as solvents to study the photobleaching of ZnPc-F7 in different solutions. Absorbance and fluorescence spectra were measured. Photobleaching kinetics were observed after irradiation for 3–180 min with ZnPc-F7 concentrations of 1–40.00μg/mL. An in vivo imaging system was used to observe the distribution and photobleaching of ZnPc-F7 in mice. ZnPc-F7 was bleached both in vitro and in vivo after exposure to laser energy at 670 nm. ZnPc-F7 was not bleached without irradiation. ‘The type of solvent, irradiation time, and initial concentration influenced the photobleaching rate. Rapid initial phases followed by a slower rate of photobleaching were observed in all four solutions. Fluorescence of ZnPc-F7 in mouse skin was steady and then increased 24 h after injection. There was no significant difference in the extent of fluorescence between normal and psoriasis-like mice. Local administration of ZnPc-F7 showed higher fluorescence intensity in skin at an early time than intravenous injection and lower content in organs after 24 h.

Keywords

• α-(8-quinolinoxy) zinc phthalocyanine
• photobleaching
• photodynamic therapy