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Inorganic materials as drug delivery systems in coronary artery stenting
Author(s) -
Karoussos I. A.,
Wieneke H.,
Sawitowski T.,
Wnendt S.,
Fischer A.,
Dirsch O.,
Dahmen U.,
Erbel R.
Publication year - 2002
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.200290004
Subject(s) - biocompatibility , restenosis , stent , neointima , coating , sirolimus , drug delivery , biomedical engineering , medicine , in vivo , neointimal hyperplasia , materials science , angioplasty , surgery , nanotechnology , metallurgy , biology , microbiology and biotechnology
Recent studies proved coronary stent implantation to be superior over conventional angioplasty in the treatment of coronary artery disease. However, restenosis remains one of the most crucial problems in interventional cardiology. Inflammatory infiltrates and foreign body reactions can be found in the tissue surrounding the struts in stenting. Thrombogenesis, proliferation of α‐actin expressing cells (smooth muscle cells) and hyperplasia of the intima occur. In order to improve the biocompatibility of the stents, new stent designs and stent coatings have been developed. One advantage of stent coating is the combination of mechanical stability of the stent with the biocompatibility of the coating. The coatings are divided into active and passive coatings. Passive coatings improve the biocompatibility of the stent, while active coatings may suppress neointima proliferation by releasing anti‐inflammatory or antiproliferative substances. Immunosuppressive drugs (tacrolimus, sirolimus) and cytostatic drugs (paclitaxel) have been tested in several studies and showed promising results. However, it could also be demonstrated that polymer‐coated stents used as a matrix for drug release reduced the hyperplasia of the intima. However, after dissipation of the immunosuppressants or cytostatics, the presence of the polymer itself lead to a delayed inflammation and proliferation causing restenosis. Thus, efforts have been made to develop inorganic coatings that are suitable for drug loading. One promising approach is a new nanoporous alumina coating. Preliminary tests with this coating revealed favourable loading characteristics and sustained drug release in vivo. The present article provides an overview on different approaches for stent coatings.