Although substantial progress in catheter and stent design has contributed to the success of percutaneous transluminal angioplasty (PTA) of atherosclerotic disease, the incidence of restenosis caused by in-stent neointimal hyperplasia remains a serious problem. Therefore, stents with a non-degradable polymer coating showing controlled release of active ingredients have become an attractive option for the site-specific delivery of anti-restenotic agents. Biodegradable coatings using polyesters, namely poly(lactic-co-glycolic acid) (PLGA) and different poly(vinyl alcohol)-graft-poly(lactic-co-glycolic acid) (PVA-g-PLGA) as paclitaxel-eluting stent coating materials were investigated here to evaluate their influence on the release kinetic. Whereas PLGA showed sigmoid release behavior, the paclitaxel release from PVA-g-PLGA films was continuous over 40 days without initial drug burst. Wide angle X-ray diffraction confirmed that paclitaxel is dissolved in the polymer matrix. Paclitaxel crystallization can be observed at a drug load of > or =10%. The effect of drug loading on polymer degradation was studied in films prepared from PVA300-g-PLGA30 with paclitaxel loadings of 5% and 15% over a time period of 6 weeks. The results suggest a surface-like erosion mechanism in films. A model stent (Jostent peripheral) coated with Parylene N, a poly(p-xylylene) (PPX) derivate, was covered with a second layer of PVA300-g-PLGA15, and PVA300-g-PLGA30 by using airbrush method. Morphology of coated stents, and film integrity after expansion from 3.12 to 5 mm was investigated by scanning electron microscopy (SEM). The devices resisted mechanical stress during stent expansion and merit further investigation under in vivo conditions.

Structured polymer fibers with diameters down to tens of nanometers are of interest for applications in filters, in composite reinforcement, or as templates for the preparation of functional nanotubes. The Figure shows fibers of poly-L-lactide produced by electrospinning from a dichloromethane solution exhibiting regular pores or pits in the 100 nm range.

The aim was to prepare fibers with diameters below the micrometer range characterized by specific bulk morphologies and surface topologies. Such materials are of interest for various applications including reinforcement, sensors or filtration as well as the formation of functional tubes by the use of fiber templates. We were able to manufacture highly structured submicrometer fibers by electrospinning from ternary solutions using polylactide (PLA) and polyvinylpyrrolidone (PVP) as polymer model components. Co-continuous phase morphologies resulted from phase separation processes taking place during fiber formation. In a subsequent step, specific surface topologies or fine pores were generated by selective removal of one of the components.

Advanced MaterialsVolume 12, Issue 9 p. 637-640 Communication Polymer, Metal, and Hybrid Nano- and Mesotubes by Coating Degradable Polymer Template Fibers (TUFT Process) M. Bognitzki, M. Bognitzki Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this authorH. Hou, H. Hou FB Chemie und Pharmazie, Institut für Organische Chemie, Johannes Gutenberg Universität Mainz, Duesbergweg 10–14, D-55099 Mainz (Germany) Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this authorM. Ishaque, M. Ishaque Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this authorT. Frese, T. Frese Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this authorM. Hellwig, M. Hellwig Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this authorC. Schwarte, C. Schwarte Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this authorA. Schaper, A. Schaper Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this authorJ. H. Wendorff, J. H. Wendorff Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this authorA. Greiner, A. Greiner FB Chemie und Pharmazie, Institut für Organische Chemie, Johannes Gutenberg Universität Mainz, Duesbergweg 10–14, D-55099 Mainz (Germany) Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this author M. Bognitzki, M. Bognitzki Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this authorH. Hou, H. Hou FB Chemie und Pharmazie, Institut für Organische Chemie, Johannes Gutenberg Universität Mainz, Duesbergweg 10–14, D-55099 Mainz (Germany) Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this authorM. Ishaque, M. Ishaque Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this authorT. Frese, T. Frese Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this authorM. Hellwig, M. Hellwig Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this authorC. Schwarte, C. Schwarte Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this authorA. Schaper, A. Schaper Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this authorJ. H. Wendorff, J. H. Wendorff Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this authorA. Greiner, A. Greiner FB Chemie und Pharmazie, Institut für Organische Chemie, Johannes Gutenberg Universität Mainz, Duesbergweg 10–14, D-55099 Mainz (Germany) Department of Chemistry & Materials Science Center, Institute of Physical Chemistry, Nuclear Chemistry, and Macromolecular Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35032 Marburg (Germany)Search for more papers by this author First published: 17 April 2000 https://doi.org/10.1002/(SICI)1521-4095(200005)12:9<637::AID-ADMA637>3.0.CO;2-WCitations: 352AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract Coating extremely thin degradable template polymer fibers with the desired wall materials forms the basis of the straightforward and highly versatile method described here for the production of polymer, metal, and hybrid nano- and mesotubes. Tubes with highly structured inner surfaces (see Figure) may be fabricated, which is of great interest for applications requiring large surface/volume ratios (see also cover). Citing Literature Volume12, Issue9May, 2000Pages 637-640 RelatedInformation