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Ma X.,University of Massachusetts Lowell | Wu T.,Vasotech, Inc. | Robich M.P.,Beth Israel Deaconess Medical Center
Interventional Cardiology | Year: 2012

Over the past decade, drug-eluting stents (DES) have greatly transformed the field of interventional cardiology. Generally, three components are included in a DES system: a metal stent platform, a drug carrier or so called 'stent coating' and a drug. As such, stent coating plays an important role in the performance of DES. This article will review the evolution of stent coatings and their role in the development of restenosis and thrombosis. © 2012 Future Medicine Ltd. Source


Grant
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase II | Award Amount: 1.13M | Year: 2010

DESCRIPTION (provided by applicant): In-stent restenosis and late-stage thrombosis, the two major polymer-associated problems occurred in existing drug eluting stents (DESs) derive a need for a new generation DES made or coated by biodegradable materials for those 14 million Americans who suffered from coronary arterial disease. However, all current biogedarable materials used in making DESs are not successful due primarily to their sever inflammatory response to stented arterial walls. VasoTech Inc. has preliminarily developed an inflammatory-free, highly biocompatible and biodegradable material--BioDe(r) material by blending Amorphous Calcium Phosphate (ACP) with Poly (Lactide-co-Glycolide) (PLGA). The major purposes of this SBIR Fast Track application are to further characterize BioDe(r) polymer's biocompatibility and degradation kinetics (Phase I), and further utilize it as drug carrier to develop a powerful new generation of DES-PowerStent by coating BioDe(r) polymer and Combo(r) drug formulation--a potent anti- restenosis formulation consisting of equal amount of Sirolimus and Paclitaxel onto VasoTech(r) metal stent. In this Fast-Track application, Phase I studies will be 1) to optimize BioDe(r) polymer formulation and its coating process (SpecificAim1), and 2) characterize the biodegradation kinetics of optimized biodegradable polymer from Specific Aim 1 study through a well established rat carotid arterial stenting model (Specific Aim 2). In Phase II, PowerStent will be created by coating developed BioDe(r) biodegradable polymer with Combo(r) anti-restenosis drug formulation onto VasoTech(r) metal stent surface. Therefore, the Specific Aims in Phase II studies will be to characterize PowerStent's drug eluting profile in rabbit iliac arterial stenting model (Specific Aim 3), and performance testing of its anti-restenosis and thrombosis functions in a pig coronary stenting model for one month (Specific Aim 4). The proposal is also our response to NIH Program Announcement (PA-06-009) entitled: Bioengineering Nanotechnology Initiative, in which the in-vivo therapeutics: a development of nanoparticles that enable controlled release of therapeutic agents, antibodies, genes and vaccines into targeted cells as described in the program announcement are perfect match to the objective of this SBIR application. Narrative: In-stent restenosis and late-stage thrombosis, the two major polymer-associated problems occurred in existing drug eluting stents (DESs) derive a need for a new generation DES made or coated by biodegradable materials for those 14 million Americans who suffered from coronary arterial disease. PowerStent--the combination of an inflammatory-free biodegradable polymer developed during Phase I studies, a potent anti-restenosis drug formulation and a featuring designed drug delivery platform as described in this SBIR Fast-Track application is such kind a stent.


Grant
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 304.52K | Year: 2008

DESCRIPTION (provided by applicant): In-stent restenosis and late-stage thrombosis, the two major polymer-associated problems occurred in existing drug eluting stents (DESs) derive a need for a new generation DES made or coated by biodegradable materials f or those 14 million Americans who suffered from coronary arterial disease. However, all current biogedarable materials used in making DESs are not successful due primarily to their sever inflammatory response to stented arterial walls. VasoTech Inc. has pr eliminarily developed an inflammatory-free, highly biocompatible and biodegradable material--BioDe(r) material by blending Amorphous Calcium Phosphate (ACP) with Poly (Lactide-co-Glycolide) (PLGA). The major purposes of this SBIR Fast Track application are to further characterize BioDe(r) polymer's biocompatibility and degradation kinetics (Phase I), and further utilize it as drug carrier to develop a powerful new generation of DES-PowerStent by coating BioDe(r) polymer and Combo(r) drug formulation--a pote nt anti- restenosis formulation consisting of equal amount of Sirolimus and Paclitaxel onto VasoTech(r) metal stent. In this Fast-Track application, Phase I studies will be 1) to optimize BioDe(r) polymer formulation and its coating process (SpecificAim1), and 2) characterize the biodegradation kinetics of optimized biodegradable polymer from Specific Aim 1 study through a well established rat carotid arterial stenting model (Specific Aim 2). In Phase II, PowerStent will be created by coating developed BioD e(r) biodegradable polymer with Combo(r) anti-restenosis drug formulation onto VasoTech(r) metal stent surface. Therefore, the Specific Aims in Phase II studies will be to characterize PowerStent's drug eluting profile in rabbit iliac arterial stenting mod el (Specific Aim 3), and performance testing of its anti-restenosis and thrombosis functions in a pig coronary stenting model for one month (Specific Aim 4). The proposal is also our response to NIH Program Announcement (PA-06-009) entitled: Bioengineering Nanotechnology Initiative, in which the in-vivo therapeutics: a development of nanoparticles that enable controlled release of therapeutic agents, antibodies, genes and vaccines into targeted cells as described in the program announcement are perfect ma tch to the objective of this SBIR application. Narrative: In-stent restenosis and late-stage thrombosis, the two major polymer-associated problems occurred in existing drug eluting stents (DESs) derive a need for a new generation DES made or coated by biodegradable materials for those 14 million Americans who suffered from coronary arterial disease. PowerStent--the combination of an inflammatory-free biodegradable polymer developed during Phase I studies, a potent anti-restenosis drug formulation an d a featuring designed drug delivery platform as described in this SBIR Fast-Track application is such kind a stent.


Ma X.,University of Massachusetts Lowell | Ma X.,Vasotech, Inc. | Oyamada S.,Brown University | Wu T.,University of Massachusetts Lowell | And 9 more authors.
Journal of Biomedical Materials Research - Part A | Year: 2011

The purpose of this study was to optimize a novel biodegradable polymer for drug eluting stent (DES) applications. Degradation profiles of different poly(D, L-lactide -co-glycolide)/amorphous calcium phosphate (PLGA/ACP) composites coated on stents were studied both in vitro and in vivo for three months. For the in vitro study, stents were immersed into the phosphate buffered saline (37°C, pH 7.4) with constant shaking. The polymer weight loss was measured weekly and morphological changes were analyzed. The results demonstrated that approximately 60% of polymer was degraded within the three-month period and there was no significant difference between the different PLGA/ACP composites. However, the composite of 50% PLGA (65/35) with 50% ACP showed a slightly faster degradation rate than other composites. Morphologically, all stent surfaces changed from a micro-porous before degradation to a corrugated solid micro-net-like structure at two months post degradation. Based on in vitro results, 65% PLGA (65/35) with 35% ACP) coated stents were selected and implanted into rat aortas (n = 12) for the in vivo study. Microscopic observation showed that no composite was found on any of the implanted stents at 12 weeks post implantation, which indicated the selected PLGA/ACP composite is desired for DES applications. © 2011 Wiley Periodicals, Inc. Source


Feng G.,Wuhan University | Xiao J.,Jinan University | Bi Y.,University of Massachusetts Lowell | Bi Y.,Vasotech, Inc. | And 16 more authors.
Journal of Biomedical Nanotechnology | Year: 2016

Our previous studies have confirmed the superior biocompatibility of the poly-L-lactic acid/amorphous calcium phosphate (PLLA/ACP) scaffolds (PowerScaffold®) compared to PLLA scaffolds and their similar 6-month radial strength compared with TAXUS® stents. In order to conduct further dynamic observations on the performance of the PowerScaffold® after 12-month implantation compared with the TAXUS® stents. Twenty PowerScaffold® and 20 TAXUS® were implanted in porcine coronary arteries. At 12-month follow-up, Quantitative Coronary Angiography showed that the stent reference vessel diameter (3.19±0.25 mm vs. 2.75±0.22 mm, p < 0.05), the mean lumen diameter (3.07±0.22 mm vs. 2.70±0.17 mm, p < 0.05) and the late lumen gain (0.45±0.07 mm vs. 0.06±0.06 mm, p < 0.01) were all significantly greater with the PowerScaffold® than the TAXUS®. As well, Intravascular Ultrasound showed the stent reference vessel area (7.74±0.48 mm2 vs. 6.96±0.51 mm2, p <0.05), the mean stent area (7.49±0.46 mm2 vs. 6.53±0.47 mm2, p < 0.05) and the mean lumen area (7.22±0.50 mm2 vs. 6.00±0.48 mm2, p < 0.01) were all significantly greater with the PowerScaffold® than the TAXUS®. The luminal patency rate of the PowerScaffold® significantly increased from 72.45±6.84% at 1 month to 93.54±8.15% at 12 months (p<0.01) while the TAXUS® stents were associated with a nonsignificant decreasing trend (89.44±8.44% vs. 86.53±8.22%). Pathology indicated the average thickness of the struts degraded by 14.25±3.04 μm at 1 month, 23.39±2.45 μm at 6 months and 35.54±2.20 μm at 12 months. Immunohistochemical examination showed that the expression of inflammatory factors NF-κB gradually decreased from 1-month to 12-month (36.79±4.78 vs. 5.79±2.85, p <0.01). As the late lumen gain of arteries implanted with the PowerScaffold® increases over time with the growth of vessels, it effectively reverse the late vascular negative remodeling observed with the TAXUS® stents, providing a better option for lumen restoration treatment in clinical practice. © 2016 American Scientific Publishers All rights reserved. Source

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