Tracheal stent
Tracheal stenosis and tracheomalacia are two diseases that causes blockage of the airway. Surgery, which is the predominant treatment of these diseases, has high risk of mortality. Current technologies employ the use of metallic and silicone stents to support and open the airway. However, these sten...
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| Format: | Final Year Project |
| Language: | English |
| Published: |
2010
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| Online Access: | http://hdl.handle.net/10356/40153 |
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| Institution: | Nanyang Technological University |
| Language: | English |
| Summary: | Tracheal stenosis and tracheomalacia are two diseases that causes blockage of the airway. Surgery, which is the predominant treatment of these diseases, has high risk of mortality. Current technologies employ the use of metallic and silicone stents to support and open the airway. However, these stents are non-viable and difficult to replace or reposition. This gave rise to research in using biodegradable polymers for stenting.
This project aims to study and understand the different drug-release profiles for biodegradable polymers (i.e. PLGA 53/47, PCL) by two different drug incorporation methods: homogeneous distribution of the drug in the matrix (monolithic system), and by spraying the drug directly onto the surface of the polymer by use of a spray-coater. The drugs used are Mitomycin C (MMC) and Dexamethasone (DXM).
In this study, the stents were fabricated to have a thickness of 250μm, length of 1.5cm and loaded with either 0.1mg or 1mg of drug. The samples’ morphologies were imaged using Scanning Electron Microscopy (SEM). The drug release study was carried out by immersing the samples in water at a temperature of 37°C. Drug stability and release were studied using reversed-phase high performance liquid chromatography (HPLC).
In general, samples with 0.1mg drug loading were more porous, achieved higher release rates, and the shorter time of exhaustion compared to those with 1mg loading. Samples incorporated with DXM also showed faster release rates compared to those with MMC. Both spray coated and dip coated systems exhibited similar release rates. Generally, the samples had low drug loading efficiency. The trends of release rates followed the Higuchi’s equations, but the quantitative analysis was not obeyed due to drug loading efficiency difference, as well as difference in the samples’ porosities.
To obtain more comprehensive results, different types of drugs and polymers should be further experimented. Methods to optimize drug loading efficiency should be studied to obtain closer agreements of theoretically and empirically derived drug release results. |
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