• Polymer(Korea)
• /
• v.34 no.2
• /
• pp.172-177
• /
• 2010

Although many researchers have studied the efficacy of paclitaxel (PTX) on many cells during the last two decades, little work has been reported on the importance of release kinetics inhibiting cell proliferation. The aim of this study is to examine the release behavior of the PTX on various biodegradable polymers such as poly(lactic-co-glycolic acid)(PLGA), poly-L-lactide (PLLA), and polycaprolactone (PCL) for drug-eluting stents (DES). The PTX from the fabricated films was released for 8 weeks and the degree of degradation of the films was observed by FE-SEM. Although the degradation time of PCL was the slowest, the PTX release rate was the fastest among them and followed by PLGA and PLLA with the equivalent PTX concentration. It suggests that hydrophobic drug such as PTX from polymer with low $T_g$ like PCL could be moved easily and released rapidly in body temperature.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.35 no.10
• /
• pp.1053-1060
• /
• 2011

This study is performed to determine the drug concentration profiles of drug-eluting stents (DES) for an ideal circular ring stent and intertwined stent models for various Reynolds numbers (Re = 200, 400, and 800). The Navier.Stokes equations coupled with the advection-diffusion equation are solved numerically in order to determine how the flow patterns and drug deposition are affected in the in-stent and post-stent regions where flow separation and recirculation occur. The presence of DES within the arterial segment affects the local drug distribution in the flow field. As a result, the drug concentration for the intertwined stent is higher over the in-stent region in comparison with the ideal stents. For a given stent geometry, the local drug concentration in the in-stent region decreases with Reynolds number, while for a given Reynolds number, the local drug concentration is relatively insensitive to the stent geometry. The results show that drug concentration along the arterial wall is significantly higher within the in-stent and post-stent regions for the intertwined stent geometry than for the ideal stent geometries.

• Korean Circulation Journal
• /
• v.48 no.11
• /
• pp.1030-1031
• /
• 2018

• Bulletin of the Korean Chemical Society
• /
• v.30 no.5
• /
• pp.1085-1087
• /
• 2009

Bare metal stents which were used to treat coronary artery disease have several biochemical problems. Polymerbased drug-eluting stents (DES) have opened up a new paradigm in the treatment of in-stent restenosis. Many studies and research programmes have proved that DES can prevent restenosis. In our study, paclitaxel-loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles have been deposited along the three dimensional scaffold of coronary stents by a method using self-assembling properties of colloidal particles. We found that the nanoparticles were deposited uniformly and closely packed. The amount of paclitaxel was easily controlled by the drug content of the nanoparticles and the deposition count.

• Biomaterials and Biomechanics in Bioengineering
• /
• v.1 no.1
• /
• pp.13-25
• /
• 2014

In the current study, a drug-eluting stent coated with biodegradable polymers and sirolimus was developed by using an ultrasonic nanocoater and characterized in aspects of surface smoothness and coating thickness. In addition, in vitro release profiles of sirolimus by changing top coating layer with different biodegradable polymers were investigated. Smooth surfaces with variable thickness could be fabricated by optimizing polymer concentration, flow rate, nozzle-tip distance, gas pressure, various solvents and ultrasonic power. Smooth surface could be generated by using volatile solvents (acetone, chloroform, and methylene chloride) or post-treating with solvent vapor. Coating thickness could be controlled by varying injection volume or polymer concentration, and higher concentration could reduce the coating time while obtaining the same thickness. The thickness measurement was the most effectively performed by a conventional cutting method among three different methods that were investigated in this study. Release profiles of sirolimus were effectively controlled by changing polymers for top layer. PLGA made the release rate 3 times faster than PDLLA and PLLA and all top layers prevented burst release at the initial phase of profiles. Our results will provide useful and informative knowledge for developing drug-eluting stents, especially coated with biodegradable polymers.

• Korean Circulation Journal
• /
• v.54 no.9
• /
• pp.519-533
• /
• 2024

The outstanding development in contemporary medicine, highlighted by percutaneous coronary intervention (PCI), was achieved through the adoption of drug-eluting stents (DESs). Although DES is the established therapy for patients undergoing PCI for de novo coronary artery disease (CAD), their drawbacks include restenosis, stent thrombosis, and the requirement for dual antiplatelet therapy (DAPT) with an uncertain duration regarding its optimality. Drug-coated balloon (DCB) treatment leaves nothing behind on the vessel wall, providing the benefit of avoiding stent thrombosis and not necessitating obligatory extended DAPT. After optimizing coronary blood flow, DCB treatment delivers an anti-proliferative drug directly coated on a balloon. Although more evidence is needed for the application of DCB treatment in de novo coronary lesions, recent studies suggest the safety and effectiveness of DCB treatment for diverse conditions including small and large vessel diseases, complex lesions like bifurcation lesions or diffuse or multivessel diseases, chronic total occlusion lesions, acute myocardial infarctions, patients at high risk of bleeding, and beyond. Consequently, we will review the current therapeutic choices for managing de novo CAD using DCB and assess the evidence supporting their concurrent application. Additionally, it aims to discuss future important perspectives.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.9
• /
• pp.1985-1988
• /
• 2009

Poly (lactic-co-glycolic acid) (PLGA) nanoparticles loading paclitaxel have been deposited on coronary stents by self-assembling properties of colloidal particles. The layers of the nanoparticles were enhanced to a sufficient mechanical strength by a thermal process under the proper temperature and humidity conditions. In vitro release studies proved the controlled paclitaxel release of the nanoparticle layers. This technique gives rise to a new range of applications for nanoparticles and drug-eluting stents.

• Applied Chemistry for Engineering
• /
• v.31 no.5
• /
• pp.502-508
• /
• 2020

Dual drug-eluting stents (DES) is a primary treatment method for coronary arterial diseases in current interventional cardiology practice. However, their pathological results according to the sequence of coating of drugs have not been reported yet. The peptide-dopamine dissolved in acetonitrile was coated onto the Chonnam National University Hospital (CNUH) stent using an electrospinning coating machine. For secondary coating (e.g., sirolimus coating, designated as SPS), sirolimus (SRL) and poly lactic-glycolic acid (PLGA) were mixed in tetrahydrofuran (THF), and the solution was then coated on the CNUH stent that had underwent the primary peptide coating using an electrospinning and spray technique. Next, the peptide-dopamine was coated on the SRL-PLGA coated stent (PSS). In this study, it was confirmed that endothelialization was promoted without being significantly affected by the coating order (SPS or PSS). The sequence of drug and peptide coating may affect the development of restenosis and PSS was effective in the prevention of restenosis compared to that of using SPS.

• The Journal of the Korea Contents Association
• /
• v.13 no.12
• /
• pp.880-892
• /
• 2013

Stent thrombosis after successful drug-eluting stent(DES) implantation has been reported in around 1% of patients in clinical trials. However, the increased risk of ST associated with DES remains a matter of concern. From 1 June 2003 to 30 June 2013, we investigated clinical characteristics, in-hospital outcomes in 10,273 patients who underwent percutaneous coronary intervention in the Heart Center of CNUH. Overall incidence of ST was 1.30% (134 patients). The incidence of ST according to the stent generations and the timing of ST (n=total, early vs. late vs. very late) were 0.79% (n=81, 26 vs. 12 vs. 43) in first-generation, 0.38% (n=39, 21 vs. 9 vs. 9) in second-generation and 0.14% (n=14, 8 vs 3 vs. 3) in third-generation, (p=0.70). The mortality from ST was significantly higher in early ST group compared to the late and very late ST groups (18.2% vs. 8.3% vs. 3.6%, p=0.042). Overall incidence of ST after DES implantation was 1.30% (134 patients). The in-hospital mortality was significantly higher in early ST group compared to the late and very late ST groups.

• 대한임상약리학회:학술대회논문집
• /
• 2005.12a
• /
• pp.6-6
• /
• 2005