Protoporphyrin Ix (Ppix) Loaded Plga Nanoparticles For Topical Photodynamic Therapy Of Melanoma Cells

Introduction: Nanoparticles (Np) can increase drug efficacy and overcome problems associated with solubility and aggregation in a solution of PpIX.Purpose: Evaluate if Np interferes in the photophysical and photobiological capacity of the PpIX comparing with free PpIX intended for topical PDT of melanoma.Methods: In vitro photophysical evaluation of Np-PpIX was carried out through singlet oxygen (O-1(2)) quantum yield. In vitro cytotoxicity and phototoxicity assays have used murine melanoma cell culture.Results: The quantum yield of singlet oxygen has shown that Np did not influence the formation capacity of this reactive species. In the dark, all PpIX-Nps concentrations were less cytotoxic compared to free drugs. At a higher light dose (1500 mJ.cm(2)) 3.91 mu g/mL PpIX had similar % viable cells for free and Np (similar to 34 %) meaning Nps did not interfere in the photodynamic effect of PpIX. However, at 7.91 mu g/mL the phototoxicity increased for both (5.8 % viable cells for free versus 21.7 % for Nps). Despite the higher phototoxicity of free PpIX at this concentration, greater cytotoxicity in the dark was obtained (similar to 49 % viable cells for free versus similar to 90 .6 % Np) which means Nps protect the tumor tissue from the photodynamic action of PpIX.Conclusions: Np is a potential delivery system for melanoma skin cancer, since it maintained the photophysical properties of PpIX and excellent in vitro phototoxicity effect against melanoma cells, reducing cell viability similar to 80 % (7.91 mu g/mL PpIX in Nps) and provides safe PDT (due to lower cytotoxicity in the dark).