Interventional cardiologists have quickly replaced bare metal stents with intravascular drug-eluting stents (DES) for treating and preventing restenosis, largely on the basis of empirical evidence that shows profound reduction in angiographic and clinical restenosis. A critical reassessment of the published evidence, however, suggests that the putative superiority of intravascular drug-eluting stents is founded on questionable premises, including overestimation of restenosis benefit, underestimation of the risk for stent thrombosis, overreliance on "soft" rather than "hard" outcomes and the attendant overestimation of cost-effectiveness. Because the long-term incremental risks, benefits, and costs of drug-eluting stents have not yet been optimally evaluated in a broad spectrum of patient and lesion cohorts, the rational role of these devices in clinical management warrants reappraisal. This book will provide a brief overview of the development of drug-eluting stents from the laboratory bench to their investigation in clinical trials and their clinical use.

There is growing interest in developing chemical and biochemical processes to obtain and modify biopolymers, and to other useful technical properties for their applications in different fields. The latest and most interesting example is chitin, it is mainly used for production of chitosan by a deacetylation reaction usually obtained in alkaline medium. Chitosan exhibits several favorable properties, such as biodegradability and biocompatibility. It also has mucoadhesive properties due to its positive charges at neutral pH that enable an ionic interaction with the negative charges of sialic acid residues of the mucus. Numerous studies have demonstrated that chitosan and its derivatives are effective and safe absorption enhancers to improve mucosal (nasal, peroral) delivery of hydrophilic macromolecules, such as peptides, proteins, and heparins. Chitosan has been developed for a variety of biomedical applications including wound dressings and drug delivery systems.

Nearly 40% of new drug candidates exhibit low solubility in water, which leads to poor oral bioavailability, high intra- and inter-subject variability and lack of dose proportionality. Modification of the physicochemical properties, such as salt formation and particle size reduction of the compound may be one approach to improve the dissolution rate of the drug. However, these methods have their own limitations. In recent years, much attention has focused on lipid based formulations to improve the oral bioavailability of poorly water soluble drugs. In fact, the most popular approach is the incorporation of the drug compound into inert lipid vehicles such as oils, surfactant dispersions, self-emulsifying formulations, emulsions and liposomes with particular emphasis on self-microemulsifying drug delivery systems (SMEDDS).