Thesis

Developing polypyrrole coated coronary stents for extended release of Sirolimus

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Awarding institution
  • University of Strathclyde
Date of award
  • 2013
Thesis identifier
  • T13665
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Abstract
  • Coronary heart disease remains the biggest killer worldwide. Amongst all the treatment options, drug-eluting stents (DES) are thought to be the most effective method of treatment for the majority of patients. Despite the early success of DES in treating coronary artery disease, concerns and uncertainties were raised. The most critical limitations are poor drug release profiles, hypersenisvity reactions and delayed endothelium healing which can lead to fatal thrombotic events. Therefore there is a need to develop a more effective DES. The aim of this work was to develop a novel DES coating with an improved drug release profile. This project investigated the potential use of conducting polymers for stent coatings in order to improve drug release profiles. Polypyrrole is a biocompatible conducting polymer with distinct chemical/physical properties. Sirolimus is a hydrophobic anti-proliferative drug which retains in the vessel wall to inhibit SMC proliferation. During this investigation polypyrole coated devices were created with the ability to release sirolimus over a therapeutically relevant period of time. Electrochemical electropolymerisation technology was used to produce a series of poylyrrole coatings on stainless steel wires. Different voltages were used during the potentiostatic electropolymerisation process. Then the coated wires were immersed in different concentrations of sirolimus to determine the relationship between electropolymerisation voltage, drug concentrations and the drug release profiles generated. To achieve this, drug-polymer coated wires were immersed in a physiological release medium and samples were taken at various time points up to 28 days, and sirolimus release was analysed using UV spectroscopy. It was found that there is a direct relationship between the concentration of the drug used in the coating solution and the drug release profile. Therefore by varying the concentration of sirolimus, an optimal drug release profile could be achieved. However no direct relationship was found between the electropolymerisation voltage level and the sirolimus release profiles. This is a preliminary study and with further research it may be possible to modify drug release profiles by varying the voltage levels.
Resource Type
DOI
Date Created
  • 2013
Former identifier
  • 1005046

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