Authors: G.A. Meerovich, I.G. Meerovich, V.G. Pevgov, E.A. Lukyanets, N.A. Oborotova, D.G. Gurevich, A.A. Zorin, V.M. Derkacheva, Z.S. Smirnova, V.B. Loschenov, G.N. Vorozhtsov, A.Yu. Baryshnikov
Affilation: A.M. Prokhorov General Physics Institute of RAS, Russian Federation
Pages: 41 - 44
Keywords: photodynamic therapy, photosensitizer, liposome size, accumulation, selectivity, efficiency
Size of nanoparticles is considered to be the one of main factors determining the efficiency of nanostructural antitumor drugs. Current work was performed to estimate the influence of liposomal size distribution on level and selectivity of accumulation in tumor and efficiency of photodynamic treatment using near IR photosensitizer Tiosens (liposomal form of (PhS)4PcAlOH) with absorption maximum at 720 nm. Tiosens liposome dispersions were prepared using Bangham technique with active substance introduced into lipid bilayer; lipid composition included mPEG2000 phosphatidyl¬ethanolamine. Particle size was reduced and unified by extrusion. Liposome size distribution was determined by laser correlation spectroscopy. It was shown that administration of Tiosens with main liposome size in a range of 90 110 nm results is level and selectivity of photosensitizer accumulation 2-3 times higher in comparison to dispersions with 250 400 nm liposome size. If photosensitizer contains liposomes of different sizes, its accumulation is determined mostly by content of fractions of 70-150 nm in diameter. Investigation of photodynamic efficiency of Tiosens have shown that use of dispersions with size of liposomes below 150 nm causes efficient tumor growth inhibition achieving 80-90%, while use of dispersions with larger size gives less pronounced effect.