title: Evaluation of photodynamic activity, photostability and in vitro drug release of zinc phthalocyanine-loaded nanocapsules.
abstract: Nanocapsule formulations containing zinc phthalocyanine (ZnPc) were investigated as drug delivery systems for use in photodynamic therapy (PDT). ZnPc loaded chitosan, PCL, and PCL coated with chitosan nanocapsules were prepared and characterized by means of their physicochemical properties, photodynamic activity, photostability and drug release profile. All formulations presented nanometric hydrodynamic radius, around 100 nm, low polydispersity index (0.08-0.24), slightly negative zeta potential for PCL nanoparticles and positive zeta potential for suspension containing chitosan. Encapsulation efficiencies were higher than 99%. The capacity of ZnPc loaded nanocapsules to produce cytotoxic singlet oxygen ((1)O2) by irradiation with red laser was monitored using 1.3-diphenylisobenzofuran as a probe. The singlet oxygen quantum yields (ΦΔ) for ZnPc loaded chitosan nanocapsules were high and similar to that of the standard (ZnPc in DMSO), displaying excellent ability to generate (1)O2. The photosensitizer loaded nanocapsules are photostable in the timescale usually utilized in PDT and only a small photobleaching event was observed when a light dose of 610J/cm(2) was applied. The in vitro drug release studies of ZnPc from all nanocapsules demonstrated a sustained release profile controlled by diffusion, without burst effect. The nature of the polymer and the core type of the nanocapsules regulated ZnPc release. Thus, the nanocapsules developed in this work are a promising strategy to be employed in PDT.
authors.affiliation: Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil.
authors.forename: Thiane Deprá
authors.initials: TD
authors.lastname: de Souza
authors.affiliation: Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil.
authors.forename: Francieli Isa
authors.initials: FI
authors.lastname: Ziembowicz
authors.affiliation: Laboratório de Espectroscopia e Polímeros, Departamento de Física, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil.
authors.forename: Debora Friedrich
authors.initials: DF
authors.lastname: Müller
authors.affiliation: Laboratório de Espectroscopia e Polímeros, Departamento de Física, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil.
authors.forename: Sâmera Cristina
authors.initials: SC
authors.lastname: Lauermann
authors.affiliation: Laboratório de Espectroscopia e Polímeros, Departamento de Física, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil.
authors.forename: Carmen Luisa
authors.initials: CL
authors.lastname: Kloster
authors.affiliation: Laboratório de Microbiologia, Centro de Ciências da Saúde, Centro Universitário Franciscano, 97010-032 Santa Maria, RS, Brazil.
authors.forename: Roberto Christ Vianna
authors.initials: RC
authors.lastname: Santos
authors.affiliation: Laboratório de Microbiologia, Centro de Ciências da Saúde, Centro Universitário Franciscano, 97010-032 Santa Maria, RS, Brazil.
authors.forename: Leonardo Quintana Soares
authors.initials: LQ
authors.lastname: Lopes
authors.affiliation: Laboratório de Nanotecnolgia, Centro Universitário Franciscano, 97010-032 Santa Maria, RS, Brazil.
authors.forename: Aline Ferreira
authors.initials: AF
authors.lastname: Ourique
authors.affiliation: Centro de Tecnologias Estratégicas do Nordeste (CETENE), Microscopia Eletrônica e Nanotecnologia, 50740-540 Recife, PE, Brazil.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Machado
authors.affiliation: Laboratório de Espectroscopia e Polímeros, Departamento de Física, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil. Electronic address: mavilletti@gmail.com.
authors.forename: Marcos Antonio
authors.initials: MA
authors.lastname: Villetti
mesh_terms: D048271:Chitosan / Q000737:chemistry* / Q000528:radiation effects; D065546:Drug Liberation; D004355:Drug Stability; D007211:Indoles / Q000737:chemistry* / Q000528:radiation effects; D054833:Isoindoles; D008027:Light; D053769:Nanocapsules / Q000737:chemistry* / Q000528:radiation effects; D009942:Organometallic Compounds / Q000737:chemistry* / Q000528:radiation effects; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000737:chemistry* / Q000528:radiation effects; D011091:Polyesters / Q000737:chemistry* / Q000528:radiation effects; D026082:Singlet Oxygen / Q000737:chemistry; D017967:Zinc Compounds
chemical_list: D007211:Indoles; D054833:Isoindoles; D053769:Nanocapsules; D009942:Organometallic Compounds; D017319:Photosensitizing Agents; D011091:Polyesters; D017967:Zinc Compounds; C052159:Zn(II)-phthalocyanine; D026082:Singlet Oxygen; C016240:polycaprolactone; D048271:Chitosan
keywords: Chitosan; Nanocapsules; Photodynamic therapy; Poly(ε-caprolactone); Zinc phthalocyanine