title: Chitosan-based nanoparticles as drug delivery systems for doxorubicin: Optimization and modelling.
abstract: In the present work, two drug delivery systems were produced by encapsulating doxorubicin into chitosan and O-HTCC (ammonium-quaternary derivative of chitosan) nanoparticles. The results show that doxorubicin release is independent of the molecular weight and is higher at acidic pH (4.5) than at physiological pH. NPs with an average hydrodynamic diameter bellow 200nm are able to encapsulate up to 70% and 50% of doxorubicin in the case of chitosan and O-HTCC nanoparticles, respectively. O-HTCC nanoparticles led to a higher amount of doxorubicin released than chitosan nanoparticles, for the same experimental conditions, although the release mechanism was not altered. A burst effect occurs within the first hours of release, reaching a plateau after 24h. Fitting mathematical models to the experimental data led to a concordant release mechanism between most samples, indicating an anomalous or mixed release, which is in agreement with the swelling behavior of chitosan described in the literature.
authors.affiliation: i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal. Electronic address: pi.soares@campus.fct.unl.pt.
authors.forename: Paula I P
authors.initials: PIP
authors.lastname: Soares
authors.affiliation: i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal.
authors.forename: Ana Isabel
authors.initials: AI
authors.lastname: Sousa
authors.affiliation: i3N/CENIMAT, Physics Department, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal.
authors.forename: Jorge Carvalho
authors.initials: JC
authors.lastname: Silva
authors.affiliation: i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal. Electronic address: imf@fct.unl.pt.
authors.forename: Isabel M M
authors.initials: IMM
authors.lastname: Ferreira
authors.affiliation: Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa, IHMT/UNL, 1349-008 Lisboa, Portugal.
authors.forename: Carlos M M
authors.initials: CMM
authors.lastname: Novo
authors.affiliation: i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal. Electronic address: jpb@fct.unl.pt.
authors.forename: João Paulo
authors.initials: JP
authors.lastname: Borges
mesh_terms: D048271:Chitosan / Q000737:chemistry*; D004317:Doxorubicin / Q000008:administration & dosage*; D004337:Drug Carriers / Q000737:chemistry*; D016503:Drug Delivery Systems; D008956:Models, Chemical; D053758:Nanoparticles / Q000737:chemistry*
chemical_list: D004337:Drug Carriers; D004317:Doxorubicin; D048271:Chitosan
keywords: Chitosan; Doxorubicin; Drug delivery; Mathematical modelling; O-HTCC