Stents coatings

Stent coatings, controbed release of antirestenotic agents from, 9 82 Stents... 

A new trend in the delivery of medicines is to employ a device component. This may be an implantable pump for insulin, a metallic stent coated with a drug, or unit capable of rapidly vaporizing a discrete dose for inhalation. Such products are regulated by the FDA as "combination" products and may be reviewed by multiple Centers within the Agency, which may require additional levels of documentation to support the product design. 

Based on the needs of certain application, the polymer should demonstrate versatile mechanical properties [e.g., stent coatings require polymers to be elastomeric and microsphere processing require them to have high glass transition temperature (7 )]. 

Park SH, Lincoff AM. Anti-inflammatory stent coatings dexamethasone and related compounds. Seminars in Interventional Cardiology SIIC 1998, 3, 191-195. 

Optimal stent implantation and new antiplatelet therapy have reduced the thrombotic complication after stent implantation, dramatically. However, thrombosis remains a challenge in some lesions and patient subgroups. As an initial and unavoidable event during stent implantation, thrombosis and platelet activation are also involved in the development of neointimal hyperplasia. Stents coated with heparin and other antithrombotic drugs have been demonstrated to decrease thrombotic complications, although their effect on neointimal hyperplasia remains uncertain. As heparin is attached to the stent surface, we divide thromboresistant stents as heparin-coated stents and drug-eluting thromboresistant stents. 

Huang (122) 2004 Jostent Biolog Pig coronary art Methotrexate 150 ng/stent Coated Yes... 

Kim (128) 2005 BiodivYsio PC Pig coronary art Carvedilol Probucol 7 ng/stent 52 ng/stent Coated Yes No... 

Recently, also biological oil-based stent coatings were introduced to deliver drugs. Advantages of these coatings are that they are metabolized by the vascular smooth muscle cells without activating inflammatory cells. 

Matsumoto Y Shimokawa H, Morishige K, et al. Reduction in neointimal formation with a stent coated with multiple layers of releasable heparin in porcine coronary arteries. J Cardiovasc Pharmacol 2002 39(4)513-522. 

Schmidmaier G, Stemberger A, Alt E, Gawaz M, Schomig A, Time release characteristics of a biodegradable stent coating... 

Alt E, Beilharz C, Preter G, et al. Biodegradable stent coating with polylactic acid, hirudin and prostacyclin reduces restenosis [abstr], J Am Coll Cardiol 1997 29 238A. 

Salu KJ, Huang Y Bosmans JM, et al. Addition of cytochalasin D to a biocompatible oil stent coating inhibits intimal hyperplasia in a porcine coronary model. Coron Artery Dis 2003 ... 

FoltsJ, Maalej N, KeaneyJ, LoscalzoJ. Palmaz-Schatz stents coated with a NO donor reduces reocclusion when placed in pig carotid arteries for 28 days [abstr], J Am Coll Cardiol I 996 27 86A. 

Wilczek KL, De Scheerder IK, Wang K, et al. Implantation of balloon expandable copper stents in porcine coronary arteries. A model for testing the efficacy of stent coating in decreasing stent thrombogenicity [abstr]. Eur Heart J 1996 I7(suppl) 455. 

Heldman AW, Cheng L, Jenkins GM, et al. Paclitaxel stent coating inhibits neointimal hyperplasia at 4 weeks in a porcine model of coronary restenosis. Circulation 2001 103( 18) 2289-2295. 

I 17 Scheller B, Schmitt A, Bohm M, Nickenig G, Atorvastatin stent coating does not reduce neointimal proliferation after coronary stenting. Z Kardiol 2003 92(12) 1025-1028,... 

I 18 Wieneke H, Dirsch O, Sawitowski T, et al. Synergistic effects of a novel nanoporous stent coating and tacrolimus on intima proliferation in rabbits. Catheter Cardiovasc Interv 2003 60(3) 399-407. 

Hausleiter J, Kastrati A, Wessely R, et al. Prevention of restenosis by a novel drug-eluting stent system with a dose-adjustable, polymer-free, on-site stent coating. Eur Heart J 2005 26(1 5) 1475-1481. 

In parallel to catheter-based delivery, stent-based approaches, such as passive stent coatings (diamond-like carbon, phosphorylcholine, and silicon carbide coatings) and immobilized drug coatings (heparin-coated stents), were evaluated for their ability to inhibit restenosis. Although animal studies demonstrated some promise, none of these technologies were clinically successful for restenosis prevention. The failure of these surface modification technologies further added to the need for the development of DES based on the principles of sustained CDD,... 

Local delivery of bevacizumab at the vessel wall can be performed by dedicated stents coated with PC. The PC polymer mimics the chemical structure of the PC headgroup, which makes up 90% of phospholipids in the outer membrane of a red blood cell. PC has been shown to decrease protein absorption and platelet adhesion thereby we can expect that the PC coating reduces the thrombus formation of the stainless steel stent, allowing the prevention of subacute thrombosis. Both in vitro and in vivo researches have demonstrated that PC-based polymers are effective in improving the biocompatibility of inert materials (60-62). 

Antithrombonic esters, including co-poly-(A,A -sebacoyl-bis-(L-leucine)-l,6-hexylene diester), (III), and polyethylene glycol derivatives, (IV), were prepared by Pacetti [3] and Hossainy [4], respectively, and used as bio-absorbable stent coatings. 

Gunn J and Cumberland D. Stent coatings and drug deliyery. Eur. Heart. J. 1999 20 1693-1700. 

Balss K, Long F, Veselov V, Akerman E, Papandreou G, Maryanoff C (2008) Multivariate analysis applied to the study of spatial distributions found in drug-eluting stent coatings by confocal Raman microscopy. Anal Chem 80 4853 859. 

Sternberg K et al. (2007) In vitro study of drug-eluting stent coatings based on poly(l-lactide)... 

Lewis AL et al. (2002) Long-term stability of a coronary stent coating post-implantation. J Biomed Mater Res 63 (6) 699-705... 

Sipos, L., Som, A., Eaust, R., 2005. Controlled deUvery of paclitaxel from stent coatings using poly(hydroxystyrene-b-isobutylene-b-hydroxystyrene) and its acetylated derivative. Biomacromolecules 6 (5), 2570-2582. 

Q. Guo, P.T. Knight, P.T. Mather, Tailored drug release from biodegradable stent coatings based on hybrid polyurethanes, J. Control. Release 137 (2009) 224-233. 

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