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Raval A.,Sardar Vallabhbhai National Institute of Technology, Surat | Parikh J.,Sardar Vallabhbhai National Institute of Technology, Surat | Engineer C.,Sahajanand Medical Technologies Pvt. Ltd.
Industrial and Engineering Chemistry Research | Year: 2011

Implantation of Drug Eluting Stents (DES) is the most accepted technique currently available to treat cardiovascular blockages. First generation DES uses polymers for drug delivery which are nondegradable in nature and remains attached to stent surface lifetime. Biodegradable polymers have gained immense attention for controlled drug delivery of therapeutic drugs from cardiovascular stents in recent times as nondegradable polymers are associated with long-term adverse events. Studies showed that permanent contact with this polymer creates local inflammatory reactions and long-term stent thrombosis which raises concerns over the widespread use of DES. Biodegradable polymers are widely accepted biomaterials in human health care area and have proved its biocompatibility as drug delivery vehicle in various medicinal applications. This research work is carried out to study mechanisms affecting drug release kinetics from coated cardiovascular stents composed of biodegradable poly lactide-co-caprolactone and polyvinyl pyrrolidone. A conventional air brush technique was effectively modified so that Co-Cr L605 metallic stents were coated within multiple layers having drug Sirolimus blended together with biodegradable polymeric matrix. Kinetic studies for drug dissolution from a stent are carried out in simulated biological fluid using high performance liquid chromatography (HPLC) with simultaneous monitoring of surface morphology by scanning electron microscopy (SEM). Drug elution data analyzed by mathematical models suggested a combination of surface drug dissolution and diffusion as major drug release mechanisms. Investigation of different top coats revealed that drug release is influenced by the hydrophobicity of the drug free protective layer. © 2011 American Chemical Society. Source


Engineer C.,Sardar Vallabhbhai National Institute of Technology, Surat | Parikh J.,Sardar Vallabhbhai National Institute of Technology, Surat | Raval A.,Sahajanand Medical Technologies Pvt. Ltd.
Chemical Engineering Research and Design | Year: 2011

The in vitro hydrolytic degradation behavior of poly(d,. l-lactide-co-glycolide) (PLGA) has been systematically investigated from the drug eluting coronary stents with respect to different copolymer compositions. The drug-polymer coated stents were incubated in phosphate buffer saline (pH 7.4) at 37 °C and 120. rpm up to 12 months to facilitate hydrolytic degradation. Gel permeable chromatography, differential scanning calorimetry and scanning electron microscopy were employed to characterize their degradation profiles. The study supports the bulk degradation behavior for PLGA from coated stents. Molecular weight of polymer decreased immediately after immersion in PBS but mass loss was not observed during first few days. The rate of hydrolytic degradation was influenced by copolymer ratio, i.e., degradation of 50:50 PLGA was fastest followed by 65:35 PLGA and 75:25 PLGA. The drug release from PLGA coated stent followed biphasic pattern which was governed by surface dissolution and diffusion of drug rather than polymer degradation. © 2010 The Institution of Chemical Engineers. Source


Thakkar A.S.,Sahajanand Medical Technologies Pvt. Ltd. | Abhyankar A.D.,Shree Bd Mehta Mahavir Heart Institute | Dani S.I.,A-Life Medical | Banker D.N.,Bankers Heart Institute | Singh P.I.,Baroda Heart Institute and Research Center
Indian Heart Journal | Year: 2012

Objectives: This study was conducted to assess the systemic drug release and distribution of sirolimus- eluting coronary stents. Methods: Twenty patients with coronary artery disease (CAD) were treated with 1, 2, or 3 a newly designed metallic stents. Blood samples were drawn at 14 time points to determine the pharma- cokinetic of sirolimus. Whole blood concentrations of sirolimus were determined by using a sen- sitive validated high-performance liquid chromatography mass spectrometry/mass spectrometry method. Results: Minimal measurable blood levels were detectable at 7 days. Across all dose levels, individ- ual Tmax values ranged from 1. 00 hour and 12. 00 hours; individual Cmax ranged from 0. 73 ng/mL and 4. 13 ng/mL. Conclusion: This study confirms the limited exposure of the systemic circulation of the eluted drug with the use of the Supralimus-Core® Sirolimus-Eluting Coronary Stent System (Sahajanand Medical Technologies Pvt. Ltd., Surat, India). In this study, sirolimus concentration in systemic circulation is to be safe, well-tolerated and short-lived. © 2012, Cardiological Society of India. All rights reserved. Source


Engineer C.,Sardar Vallabhbhai National Institute of Technology, Surat | Parikh J.,Sardar Vallabhbhai National Institute of Technology, Surat | Raval A.,Sahajanand Medical Technologies Pvt. Ltd.
Trends in Biomaterials and Artificial Organs | Year: 2011

Biodegradable polymers are extensively used in medical device industry for the controlled delivery of pharmaceutical agent to the targeted region. Successful performance of any controlled drug delivery system (DDS) relies on the drug elution kinetics which further depends on the degradation behavior of the biodegradable polymers. Thus, fundamental understanding of the polymer degradation phenomena is the important aspect in the design and development of controlled drug delivery system. Polymer degradation is the complex phenomena known to be affected by the various inter-related factors such as polymer physico-chemical properties, drug-polymer interaction, preparation technique, degradation environment, etc. This article intends to provide the overview of the degradation mechanisms of biodegradable polymers, factors influencing the degradation, advanced characterization techniques of polymer degradation, various modeling approach to study polymer degradation and influence of polymer degradation on biocompatibility. Source


Raval A.,Sardar Vallabhbhai National Institute of Technology, Surat | Parikh J.,Sardar Vallabhbhai National Institute of Technology, Surat | Engineer C.,Sahajanand Medical Technologies Pvt. Ltd.
Chemical Engineering Research and Design | Year: 2010

Targeted drug delivery systems are used to minimize the adverse effects of the pharmaceutical agents while maintaining the high local drug concentrations. To minimize post-angioplasty complications like tissue hyperplasia and related restenotic events, cardiovascular stents coated with anti-inflammatory, anti-proliferative agents have been proposed. The efficacy and toxicity of local therapeutics depends upon drug release kinetics which will further decide drug deposition, distribution, and retention at the target site. Drug eluting stents (DES) presently possesses clinical importance as an alternative to coronary artery bypass grafting due to ease of procedure and comparable safety and efficacy. This paper focuses on preparation and evaluation of controlled drug release biodegradable systems for stent base drug delivery providing insight of the drug elution mechanism which ultimately governs release kinetics. Multiple layers of dexamethasone-biodegradable polymers were successfully spray coated on Co-Cr alloy L605 metallic stents by modified air brush technique. In vitro drug elution data acquired by high performance liquid chromatography (HPLC) revealed that release of dexamethasone can be modulated up to 3 weeks by optimized use of blends of biodegradable poly- l-lactide-co-caprolactone and polyvinyl pyrrolidone. Surface investigation by scanning electron microscopy (SEM) represented smooth surface finish without any irregularities suggesting the efficacy of utilization of optimal coating parameters for multiple layer coating. © 2010 The Institution of Chemical Engineers. Source

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