Nanostructured delivery system for zinc phthalocyanine: preparation, characterization, and phototoxicity study against human lung adenocarcinoma A549 cells
Mariana da Volta Soares1, Mainara Rangel Oliveira1, Elisabete Pereira dos Santos1, Lycia de Brito Gitirana2, Gleyce Moreno Barbosa3, Carla Holandino Quaresma3, Eduardo Ricci-Júnior1
1Department of Medicines, Laboratório de Desenvolvimento Galênico (LADEG), Faculty of Pharmacy, 2Laboratory of Animal and Comparative Histology, Glycobiology Research Program, Institute of Biomedical Science, 3Department of Medicines, Laboratório Multidisciplinar de Ciências Farmacêuticas, Faculty of Pharmacy, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
Abstract: In this study, zinc phthalocyanine (ZnPc) was loaded onto poly-ε-caprolactone (PCL) nanoparticles (NPs) using a solvent emulsification–evaporation method. The process yield and encapsulation efficiency were 74.2% ± 1.2% and 67.1% ± 0.9%, respectively. The NPs had a mean diameter of 187.4 ± 2.1 nm, narrow distribution size with a polydispersity index of 0.096 ± 0.004, zeta potential of -4.85 ± 0.21 mV, and spherical shape. ZnPc has sustained release, following Higuchi’s kinetics. The photobiological activity of the ZnPc-loaded NPs was evaluated on human lung adenocarcinoma A549 cells. Cells were incubated with free ZnPc or ZnPc-loaded NPs for 4 h and then washed with phosphate-buffered saline. Culture medium was added to the wells containing the cells. Finally, the cells were exposed to red light (660 nm) with a light dose of 100 J/cm2. The cellular viability was determined after 24 h of incubation. ZnPc-loaded NPs and free photosensitizer eliminated about 95.9% ± 1.8% and 28.7% ± 2.2% of A549 cells, respectively. The phototoxicity was time dependent up to 4 h and concentration dependent at 0–5 µg ZnPc. The cells viability decreased with the increase of the light dose in the range of 10–100 J/cm2. Intense lysis was observed in the cells incubated with the ZnPc-loaded NPs and irradiated with red light. ZnPc-loaded PCL NPs are the release systems that promise photodynamic therapy use.
Keywords: photosensitizer, nanoparticles, photodynamic therapy, lung cancer, phototoxicity, biodistribution