ABSTRACT
From the use of botanical plants in early human civilizations through synthetic chemistry and biotechnology, drug research has always passionate scientists creating exciting challenges to a large number of researchers from different fields, thus promoting a collaborative effort between polymer scientists, pharmacologists, engineers, chemists, and medical researchers. Worldwide, there is an increasing concern on health care that creates a major opportunity for development of new pharmaceutical formulations. Ageing
populations worried about the quality of life in the older years are actively seeking for new, more effective and patient compliant drug delivery devices. This has been the driving force for the continuous growth of the research made on delivery devices, which has become a powerful technique in health care. It has been recognized for long that simple pills or injections may not be the suitable methods of administration of a certain active compound. These medications present several problems and/or limitations, like poor drug bioavailability and systemic toxicity, derived essentially from pharmacokinetic and other carrier limitations and low solubility of the drugs in water. Therefore and to overcome these drawbacks, clinicians recommend frequent drug dosing, at high concentrations in order to overcome poor drug bioavailability but causing a potential risk of systemic toxicity. Polymer science has open new strategies for drug delivery systems. This chapter overviews of possible strategies involving polymer modification and processing for controlled drug delivery and drug delivery in tissue engineering. 12.1 Controlled Drug Delivery SystemsA controlled drug release system consists in a drug carrier capable of releasing the bioactive agent in a specific location at a specific rate [1]. The main purpose of these controlled release systems is to achieve a more effective therapy, that is, a system with a delivery profile that would yield a high blood level of the drug over a long period of time, avoiding large fluctuations in drug concentration and reducing the need of several administrations. Furthermore, these systems often improve the drug performance, provide patient compliance, and prolong drug stability. It is of particular interest the key role that materials have in the development of these new drug delivery systems, from polymers to ceramics or even metals [2-4]. When a pharmaceutical agent is encapsulated within, or attached to, a polymer or lipid, drug safety and efficacy can be greatly improved and new therapies are possible. This has been the driving force for active study of the design of these materials, intelligent delivery systems and approaches for delivery through different administration routes [5]. Drug delivery systems are usually classified according to the mechanism that controls the release of the active compound.
