Primary Screening of Photosensitizers of the Bacteriochlorin Series for Photodynamic Therapy of Malignant Neoplasms

Abstract

Primary screening of photosensitizers of the bacteriochlorin series containing aminoamide, propyl, and carbohydrate substituents was carried out; it included an assessment of spectral characteristics of these compounds, their storage stability in solution under darkened conditions and light exposure, and the study of photoinduced activity and cytotoxicity on tumor of HEp2 cells. According to the results of absorption and fluorescence analyzes, dyes with aminoamide substituents had a maximum at 754 ± 2 nm, are not stable during storage (fluorescence intensity decreased by 33–56% during a day); compounds with propyl and carbohydrate substituents absorbed in the region of 780–831 nm were characterized by stability during storage and irradiation. All PS except the dye with the carbohydrate residue in the exocycle E, exhibited photoinduced activity and lack of dark toxicity. The highest photoactivity was detected in compounds with aminoamide fragments in the macrocyclic ring (during 2 h-incubation the IC₅₀ ranged from 17 nM to 49 nM). Taking into consideration physicochemical and biological properties, as well as technology of production and stability during storage and irradiation, O-propyloxime-N-propoxybacteriopurinimide methyl ester was chosen for further research aimed at creating a new PS generation for photodynamic therapy of malignant tumors.