Controlled Release and Nanotechnology

Abstract

Nanosized controlled release systems for drug delivery are segregated into several categories including polymeric nanoparticles, liposomes, solid lipid nanoparticles, polymeric micelles, and dendrimers. This topic is extensive and as such is only briefly reviewed here. More detailed information may be found in more focused chapters of this book. With this in mind, this chapter will provide an overview of nanoparticulate systems, followed by some of the more interesting opportunities and applications of nanotechnology in controlled release: metal–organic systems, nanotubes, responsive systems, and personal care products. The use of a drug as a therapeutic agent is often a delicate balance between therapeutic efficacy and detrimental side effects including toxicity. The control of the amount of drug delivered over time and the spatial localization of that delivery are paramount in overcoming the challenges of providing optimal therapy. This challenge drives the design of various drug delivery strategies that strive to revolutionize the way drugs exert their actions. Much of this attention has focused on nanoparticles due to their small size, relatively high surface area, influence on biodistribution, ability to make drugs available for intravascular delivery, their stabilizing effect on therapeutic agents, and the capability of sustaining release of the agent (Mainardes and Silva 2004). All these elements ultimately lead to more effective delivery of the active agent to a desired physiological or pathophysiological location. Modification of the nanocarrier composition largely controls the release of the active agent from the carrier. This can be accomplished by using various types of polymers or lipids, changing the molecular weight of those components, or changing the surface characteristics such as by crosslinking or adding a separate component like poly (ethylene glycol). In addition, more specific modifications can be made in order to achieve the optimal controlled drug release from the nanodevice. The following reviews the major classes of nanoscale drug delivery devices.