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Title:Modeling and simulation of coronary stents: Intravascular drug delivery and arterial drug distribution
Author(s):Zhu, Xiaoxiang
Advisor(s):Braatz, Richard D.
Department / Program:Chemical & Biomolecular Engr
Discipline:Chemical Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):drug-eluting stents
hydrophobic drug
mathematical modeling
intravascular delivery
reversible binding
Abstract:In-stent restenosis still occurs in coronary arteries implanted with drug-eluting stents, with the maximum thickness observed at the vascular site of maximum inter-strut angle. This phenomenon may be related to the specific spatiotemporal drug uptake in the arterial wall. In this work local delivery of a hydrophobic drug from a drug-eluting stent implanted in a coronary artery is investigated using a mathematical model that couples drug diffusion and reversible binding in the arterial wall. The model is solved by the finite volume method with varied stent-coating and vascular diffusivities for (i) drug loading at concentrations less than or equal to the solubility, and (ii) high drug loading at concentrations greater than the solubility. Drug release profiles in the coating are observed to depend not only on the coating diffusivity but also on the properties of the surrounding arterial wall. Distinguished dependence on the vascular diffusivity and coating diffusivity of the spatially-averaged drug levels in the wall at quasi-steady state are discussed. Anisotropic drug diffusivities result in similar average drug levels in the arterial wall but very different spatial distributions. Higher circumferential vascular diffusivity results in more uniform drug loading in the upper layers and is potentially beneficial in reducing in-stent restenosis. An analytical expression is derived for determining whether higher free-drug concentration than that of bound-drug can occur in the arterial wall.
Issue Date:2011-01-21
Rights Information:Copyright 2010 Xiaoxiang Zhu
Date Available in IDEALS:2011-01-21
Date Deposited:2010-12

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