A comparative study of the photophysical and phototoxic properties of octakis(decyloxy) phthalocyaninato zinc(II), incorporated in a hydrophilic polymer, in liposomes and in non-ionic micelles

Factors such as charge, aggregation and lipophilicity influence photosensitiser localisation. The lipophilic octasubstituted sensitiser 2,3,9,10,16,17,23,24-octakis(decyloxy) phthalocyaninato zinc(II) was incorporated into liposomes of dimyristoyl-L-alpha-phosphatidylcholine (DMPC), non-ionic micelles of Tween 80 and the hydrosoluble polymer Solutol(R) HS 15 in order to investigate how these different environments affect the photophysical properties and phototoxicity of the photosensitiser. Fluorescence quantum yields and singlet molecular oxygen generation are enhanced in the presence of Solutol(R) HS 15. Phototoxicities were calculated by employing a concentration of 10(-7) M of the dye against the Hep-2 cell line, which showed a viability of 53 and 30% in DMPC and Solutol(R) HS 15, respectively. After 24 h of photodynamic therapy with 15 min irradiation, apoptotic and necrotic cells were observed.