In this study, development of modified release tablet formulations containing diltiazem hydrochloride-loaded microspheres to be taken once rather than two or three times a day was attempted. For this purpose, ethylcellulose microspheres were prepared by emulsion-solvent evaporation technique. The influence of emulsifier type and drug/polymer ratio on production yield, encapsulation efficiency, particle size, surface morphology and in-vitro release characteristics of the microspheres was evaluated. Suitable microspheres were selected and tabletted using different tabletting agents, Ludipress, Cellactose80, Flow-Lac100 and excipients Compritol888 ATO, KollidonSR. Tablets were evaluated from the perspective of physical and in-vitro drug release characteristics. It was seen that type and ratio of the excipients played an important role in the tabletting of the microspheres. As a result, two tablet formulations containing 180 mg diltiazem hydrochloride and using either Compritol888 ATO or KollidonSR were designed successfully and maintained drug release for 24 h with zero order and Higuchi kinetics, respectively.
Cardiovascular diseases are still one of the major causes of death for the people in the world. Biomedical implantable devices are the basic approach on the treatment of cardiovascular diseases. However, unexpected and serious complications can be observed in the case of their usage. Nanotechnology gives a promising perspective to overcome these drawbacks. Nanoparticulate drug delivery systems have develop superior medical solutions and offer better prospects to patients. This review comprehensively summarizes the recent situation, the benefits and the role of nanocarriers in cardiovascular implant technology. preserve or regain its patency. Balloon angioplasty was the common choice to open the blocked vascular vessels before the introduction of coronary stents as bare metallic stents [16]. However, both stent implantation and balloon angioplasty are still cause of various complications, such as elastic recoil, vascular smooth muscle cell migration and proliferation, platelet aggregation, and at last thrombus formation [17,18]. These complications were eventually overcome by the modifications in the stent technology and could be ameliorated by the introduction of therapeutic compounds. In this context, drug eluting stents have been developed through coating the surface of the stents by a matrix polymer, bearing therapeutic agents that regulate the cell division and prevent thrombosis. Sirolimus-, biolimus-, everolimus-and paclitaxel-polymer combinations have been the major surface modifiers which are used for the surface coating and the manufacturing of the drug eluting stents [19,20]. Among them, paclitaxel-eluting TAXUS ® and sirolimus-eluting CYPHER ® are the most under-researched implanted stents in this field. The conducted randomized clinical studies have demonstrated that these systems had indicated their therapeutic efficiencies by reducing the risk of in-stent restenosis [21,22]. Even though the surface coating of the stents by drug-polymer combination has solved the problem of instent restonosis, a new critical problem surfaces after then-late stent thrombosis. This trouble is partly due to the introduction of the stent surface as a foreign substance by human body and also partly due to the incorporation of the polymers, which even they have biodegradable structure, causes inflammation and increases the sensitivity to thrombosis [23,24]. In fact, the majority of the drug eluting stents over bare metallic stents is still contradictive for these reasons. At this point, the researchers have found the solution in nanotechnology. The combination of nanotechnology with cardiovascular device provides a key to the solution by inducing the endothelial cells proliferation, while suppressing the vascular smooth muscle cell proliferation at the same time. From this perspective, nanostructured stents seem more effective in the treatment of cardiovascular disease compared to nanocarrier based stent coatings. When nanoparticles are associated with stents, the particles leaves from the stent surface, penetrate to
The aim of this research was to investigate the effect of the duration of ultrasonication energy on the physicochemical characteristics of the nano–sized particulate drug delivery systems. For this purpose, meloxicam-loaded vitamin E d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS)-emulsified poly (D,L–lactide–co-glycolide) (PLGA) nanoparticles were designed by using ultrasonication-solvent evaporation technique and were characterized by photon correlation spectroscopy for size and size distribution, scanning electron microscopy for surface morphology and laser Doppler anemometry for surface charge. Ultraviolet -spectrophotometer was used to measure the drug encapsulation efficiency and to obtain in vitro drug release profile. The results showed that the physicochemical properties of the prepared nanoparticles are effectively controlled by the amount of shear stress transferred from the energy source to the emulsion, which is strongly correlated to the ultrasonication time.
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