title: Mathematical modeling of drug release from nanostructured porous Si: combining carrier erosion and hindered drug diffusion for predicting release kinetics.
abstract: A novel, empirical, macroscopic model is developed to describe the release of a model anticancer drug, Mitoxantrone, from native and chemically modified porous Si (PSi) thin films. Drug release from these carriers results from a combination of two mechanisms, i.e. out-diffusion of the drug molecules and erosion of the Si scaffold. Thus, the proposed mathematical model adapts the Crank model to lump the effects of temporal changes in molecular interactions and carrier scaffold erosion into a comprehensive model of hindered drug diffusion from nanoscale porous systems. Careful characterization of pore size, porosity, surface area, drug loading, as well as Si scaffold degradation profiles, measured over the same time-scale as drug release, are incorporated into the model parameter estimation. A comparison of the experimental and model results shows accurate representation of the data, emphasizing the reliability of the model. The proposed model shows that drug diffusivity values significantly vary with time for the two studied carriers, which are ascribed to the distinctive role of the prevailing physical mechanisms in each system. Finally, secondary validation of the proposed model is demonstrated by showing adequate fit to published data of the release of dexamethasone from similar mesoporous Si carriers.
authors.affiliation: The Interdepartmental Program of Biotechnology, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Adi
authors.initials: A
authors.lastname: Tzur-Balter
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Young
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Bonanno-Young
authors.forename: Ester
authors.initials: E
authors.lastname: Segal
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry; D003198:Computer Simulation; D004058:Diffusion; D007700:Kinetics; D008422:Materials Testing; D008942:Mitoxantrone / Q000008:administration & dosage / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D053769:Nanocapsules / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D016062:Porosity; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D000970:Antineoplastic Agents; D053769:Nanocapsules; D008942:Mitoxantrone; D012825:Silicon
keywords: Controlled delivery; Drug release; Mathematical modeling; Mesoporous Si; Surface chemistry