title: Diffusion-Based Design of Multi-Layered Ophthalmic Lenses for Controlled Drug Release.
abstract: The study of ocular drug delivery systems has been one of the most covered topics in drug delivery research. One potential drug carrier solution is the use of materials that are already commercially available in ophthalmic lenses for the correction of refractive errors. In this study, we present a diffusion-based mathematical model in which the parameters can be adjusted based on experimental results obtained under controlled conditions. The model allows for the design of multi-layered therapeutic ophthalmic lenses for controlled drug delivery. We show that the proper combination of materials with adequate drug diffusion coefficients, thicknesses and interfacial transport characteristics allows for the control of the delivery of drugs from multi-layered ophthalmic lenses, such that drug bursts can be minimized, and the release time can be maximized. As far as we know, this combination of a mathematical modelling approach with experimental validation of non-constant activity source lamellar structures, made of layers of different materials, accounting for the interface resistance to the drug diffusion, is a novel approach to the design of drug loaded multi-layered contact lenses.
authors.affiliation: Department of Mechanical Engineering and IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.|Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.
authors.forename: Andreia F R
authors.initials: AF
authors.lastname: Pimenta
authors.affiliation: Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.|CIIEM, Instituto Superior de Ciências da Saúde Egas Moniz, Caparica, Portugal.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Serro
authors.affiliation: Department of Mechanical Engineering and IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.|Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Paradiso
authors.affiliation: Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.
authors.forename: Benilde
authors.initials: B
authors.lastname: Saramago
authors.affiliation: Department of Mechanical Engineering and IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.
authors.forename: Rogério
authors.identifier: http://orcid.org/0000-0001-7374-6741
authors.initials: R
authors.lastname: Colaço
mesh_terms: D000890:Anti-Infective Agents / Q000008:administration & dosage*; D002710:Chlorhexidine / Q000008:administration & dosage*; D003198:Computer Simulation; D003261:Contact Lenses; D003692:Delayed-Action Preparations / Q000737:chemistry*; D004058:Diffusion; D016503:Drug Delivery Systems / Q000295:instrumentation*; D065546:Drug Liberation; D006801:Humans; D020100:Hydrogels / Q000737:chemistry; D064704:Levofloxacin / Q000008:administration & dosage*; D008689:Methacrylates / Q000737:chemistry; D008956:Models, Chemical
chemical_list: D000890:Anti-Infective Agents; D003692:Delayed-Action Preparations; D020100:Hydrogels; D008689:Methacrylates; C005044:hydroxyethyl methacrylate; D064704:Levofloxacin; D002710:Chlorhexidine