title: Chloroaluminium phthalocyanine polymeric nanoparticles as photosensitisers: photophysical and physicochemical characterisation, release and phototoxicity in vitro.
abstract: Nanoparticles of poly(d,l-lactide-co-glycolide), poly(d,l-lactide) and polyethylene glycol-block-poly(d,l-lactide) were developed to encapsulate chloroaluminium phthalocyanine (AlClPc), a new hydrophobic photosensitiser used in photodynamic therapy (PDT). The mean nanoparticle size varied from 115 to 274 nm, and the encapsulation efficiency ranged from 57% to 96% due to drug precipitation induced by different types of polymer. All nanoparticle formulations presented negative zeta potential values (-37 mV to -59 mV), explaining their colloidal stability. The characteristic photophysical parameters were analysed: the absorption spectrum profile, fluorescence quantum yield and transient absorbance decay, with similar values for free and nanoparticles of AlClPc. The time-resolved spectroscopy measurements for AlClPc triplet excited state lifetimes indicate that encapsulation in nanocapsules increases triplet lifetime, which is advantageous for PDT efficiency. A sustained release profile over 168 h was obtained using external sink method. An in vitro phototoxic effect higher than 80% was observed in human fibroblasts at low laser light doses (3 J/cm(2)) with 10 μM of AlClPc. The AlClPc loaded within polymeric nanocapsules presented suitable physical stability, improved photophysical properties, sustained released profile and suitable activity in vitro to be considered a promising formulation for PDT.
authors.affiliation: Programa de Pós-Graduação em Nanotecnologia Farmacêutica, Universidade Federal de Ouro Preto, Campus Universitário Morro do Cruzeiro, Ouro Preto, MG 35400-000, Brazil.
authors.forename: Carina Silva
authors.initials: CS
authors.lastname: de Paula
authors.forename: Antonio Cláudio
authors.initials: AC
authors.lastname: Tedesco
authors.forename: Fernando Lucas
authors.initials: FL
authors.lastname: Primo
authors.forename: José Mário Carneiro
authors.initials: JM
authors.lastname: Vilela
authors.forename: Margareth Spangler
authors.initials: MS
authors.lastname: Andrade
authors.forename: Vanessa Carla Furtado
authors.initials: VC
authors.lastname: Mosqueira
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D005347:Fibroblasts / Q000187:drug effects; D006801:Humans; D007211:Indoles / Q000008:administration & dosage / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D053769:Nanocapsules / Q000008:administration & dosage / Q000737:chemistry*; D054118:Nanospheres / Q000008:administration & dosage / Q000737:chemistry*; D009942:Organometallic Compounds / Q000008:administration & dosage / Q000737:chemistry*; D017319:Photosensitizing Agents / Q000008:administration & dosage / Q000737:chemistry*; D011108:Polymers / Q000008:administration & dosage / Q000737:chemistry*; D012995:Solubility
chemical_list: D007211:Indoles; D053769:Nanocapsules; D009942:Organometallic Compounds; D017319:Photosensitizing Agents; D011108:Polymers; C044797:chloroaluminum phthalocyanine