Comparative Study of the Photocytotoxicity of Two Liposomal Forms of Chlorin E6

The effectiveness of two liposomal forms of the photosensitizer chlorin E6 differing in their method of preparation was compared. Two types of liposomes were obtained: one containing chlorin E6 in the lipid bilayer; the other, containing the trisodium salt of chlorin E6 in the internal medium. The effectiveness of the prepared liposomes as means for photodynamic therapy (PDT) was studied on L929 mouse fibroblast cell culture. Phototoxicity was estimated upon irradiation with light of wavelength 660 nm and energy density 30 J/cm 2 . The results showed higher phototoxicity of both liposomal forms of chlorin E6 as compared to the free form of the substance. In turn, liposomes with chlorin E6 included in the lipid bilayer were more phototoxic than liposomes containing the substance in the internal medium. The most probable reason for this phenomenon may be more efficient intracellular accumulation of the active substance for chlorin E6 included in the liposome bilayer.