title: Examination of drug release and distribution from drug-eluting stents with a vessel-simulating flow-through cell.
abstract: The recently introduced vessel-simulating flow-through cell offers new possibilities to examine the release from drug-eluting stents in vitro. In comparison with standard dissolution methods, the additional compartment allows for the examination of distribution processes and creates dissolution conditions which simulate the physiological situation at the site of implantation. It was shown previously that these conditions have a distinct influence on the release rate from the stent coating. In this work, different preparation techniques were developed to examine the spatial distribution within the compartment simulating the vessel wall. These methods allowed for the examination of diffusion depth and the distribution resulting in the innermost layer of the compartment simulating the vessel wall. Furthermore, the in vitro release and distribution examined experimentally were modelled mathematically using finite element (FE) methods to gain further insight into the release and distribution behaviour. The FE modelling employing the experimentally determined diffusion coefficients yielded a good general description of the experimental data. The results of the modelling also provided important indications that inhomogeneous coating layer thicknesses around the strut may result from the coating process which influence release and distribution behaviour. Taken together, the vessel-simulating flow-through cell in combination with FE modelling represents a unique method to analyse drug release and distribution from drug-eluting stents in vitro with particular opportunities regarding the examination of spatial distributions within the vessel-simulating compartment.
authors.affiliation: Institute of Pharmacy, Biopharmaceutics and Pharmaceutical Technology, EMA University of Greifswald, Greifswald, Germany. anne.seidlitz@uni-greifswald.de
authors.forename: Anne
authors.initials: A
authors.lastname: Seidlitz
authors.forename: Stefan
authors.initials: S
authors.lastname: Nagel
authors.forename: Beatrice
authors.initials: B
authors.lastname: Semmling
authors.forename: Niels
authors.initials: N
authors.lastname: Grabow
authors.forename: Heiner
authors.initials: H
authors.lastname: Martin
authors.forename: Volkmar
authors.initials: V
authors.lastname: Senz
authors.forename: Claus
authors.initials: C
authors.lastname: Harder
authors.forename: Katrin
authors.initials: K
authors.lastname: Sternberg
authors.forename: Klaus-Peter
authors.initials: KP
authors.lastname: Schmitz
authors.forename: Heyo K
authors.initials: HK
authors.lastname: Kroemer
authors.forename: Werner
authors.initials: W
authors.lastname: Weitschies
mesh_terms: D004333:Drug Administration Routes; D066298:In Vitro Techniques; D010599:Pharmacokinetics; D015607:Stents