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Background Introduction of Bare Metal Stents (BMS) was itself a revolutionary step in the history of the medical industry; however, Drug Eluting Stents (DES) maintained its superiority over BMS in every aspect from restenosis rate to late lumen loss. The reason behind the magnanimous position of the DES in the stent market is the degree of improvement with which it evolves. New and better stents come into the market every year, surpassing their predecessors by many folds. Literature review This review paper discusses the journey of DES with supporting clinical trials in detail. In the first generation, there were stainless-steel stents with thicker coatings. Although they had superior results compared to BMS, there was still room for improvement. Afterward came the second-generation stents, which had superior metal platforms with thinner struts and thin coatings. The drugs were also changed from Paclitaxel and Sirolimus to Zotrolimus and Everolimus. These stents performed best; however, there was an issue of permanent coating, which remained intact over the stent surface after complete drug elution and started to cause issues in longer-term studies. Hence, an improved version of DES was introduced to these permanent coatings called the third generation of drug eluting stents, which initially utilized biodegradable polymer and ultimately moved towards polymer free drug coatings. This generation has introduced a unique amalgam of technologies to achieve its polymer free coatings; however, researchers have numerous prospects of growth in this field. This review paper highlights the major coups of stent technology evolution from BMS to DES, from thick polymeric coatings to thin coatings and from durable polymers to polymer free DES. Conclusion In conclusion, though the medical industry promptly accepted BMS as the best treatment option for cardiovascular diseases; however, DES has provided even better results than BMS. In DES, the first and second generation has ruled the technology for many years and are still on the shelves. Still, the issues aroused due to durable polymer shifted the attention towards biodegradable drug eluting stents, the third generation growing rapidly. But the scientific community has not restricted themselves and is investigating bioresorbable stents that completely eliminate the polymer intervention in drug eluting stent technology.

Cardiovascular diseases are becoming a leading cause of death in the world, and attention is being paid to develop natural drug-based treatment to cure heart diseases. Curcumin, ginger, and magnolol are pharmaceutically active in many ways, having properties including anticoagulation, antiproliferation, anti-inflammatory, and antioxidant, and may be used to synthesis coatings for drug-eluting stents to treat cardiovascular diseases. In the present investigation, a degradable polymer with varying molecular weights was used as a drug carrier to control the degradation of polymer; three different natural drugs such as curcumin, magnolol, and ginger were used owing to their reported pharmacological properties. The results of in vitro measurements of all three natural drugs released from drug-loaded polymeric films showed an initial burst release followed by a sustained release for up to 38 days of measurement. On the other hand, different levels of hemocompatibility were observed by varying concentrations of natural drugs in human erythrocytes. As per the ASTM F756 standard, ginger having low concentration showed optimum hemocompatibility with regard to the drug-eluting stent application as compared with magnolol and curcumin concentrations, which showed suboptimal hemocompatibility and fall in the range of mild-to-severe blood toxicity category. The structure of the coating films was characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) with results suggesting that there was no chemical bonding between the polymer and drug. Thus, according to this study, it can be concluded that after more detailed in vitro testing such as hemocompatibility tests and platelet adhesion testing, ginger can be a better candidate as a drug-coating material for drug-eluting stent applications.

The study focuses on the development of novel Aloe vera based polymeric composite films and antimicrobial suture coatings. Polyvinyl alcohol (PVA), a synthetic biocompatible and biodegradable polymer, was combined with Aloe vera, a natural herb used for soothing burning effects and cosmetic purposes. The properties of these two materials were combined together to get additional benefits such as wound healing and prevention of surgical site infections. PVA and Aloe vera were mixed in a fixed quantity to produce polymer based films. The films were screened for antibacterial and antifungal activity against bacterial (E. coli, P. aeruginosa) and fungal strains (Aspergillus flavus and Aspergillus tubingensis) screened. Aloe vera based PVA films showed antimicrobial activity against all the strains; the lowest Aloe vera concentration (5%) showed the highest activity against all the strains. In vitro degradation and release profile of these films was also evaluated. The coating for sutures was prepared, in vitro antibacterial tests of these coated sutures were carried out, and later on in vivo studies of these coated sutures were also performed. The results showed that sutures coated with Aloe vera/PVA coating solution have antibacterial effects and thus have the potential to be used in the prevention of surgical site infections and Aloe vera/PVA based films have the potential to be used for wound healing purposes.

Drug eluting stents (DES) can efficiently reduce the atherosclerosis and restenosis issues of coronary artery as compared to bare metal stents due to the presence of pharmaceutically active agent on their surface. Nevertheless, the arising safety concerns of DES such as delayed healing and late in stent restenosis and thrombus, has stirred the research efforts to improve the outcomes of the DES. In this connection, attention is being shifted from the use of synthetic drug to natural drug for DES. In the present work, natural compound loaded polymeric films were synthesized and their antioxidant and anticoagulation capabilities were assessed through in vitro testing. The potential of the drug loaded polymeric films to curb the production of free radicals was evaluated by carrying out antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The in vitro platelet adhesion was investigated through static platelet adhesion test while effect of synthesized films on intrinsic coagulation pathway was investigated through activated partially thromboplastin time (APTT). Moreover, to further evaluate the blood compatibility of the developed drug loaded films, in vitro hemolytic and anti-thrombolytic assays were carried out. The obtained results indicated that, incorporating herbal compounds such as ginger, magnolol and curcumin, in polymeric matrix (PVA) has significantly improved the blood compatibility of the polymeric films. Hence, it can be concluded that the synthesized drug loaded polymeric films have the potential capability to be used as a potential coating material for coating biomedical implants with good anticoagulation and antioxidant property to cater the cardiovascular issues such as atherosclerosis, restenosis and thrombus formation.

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