ABSTRACT
Nanoscale materials have been extensively used in diverse applications, such as electronics, textiles (Perelshtein et al. 2008), agriculture (Rai and Ingle 2012), and biomedicine (Parveen et al. 2012). Nanotechnology has attracted great attention in the pharmaceutical area with the development of drug-loaded particles with a diameter < 1,000 nm (Brigger et al. 2002). Nanoparticles (NPs) are solid systems classifi ed into nanospheres and nanocapsules depending on the type of polymer, the localization of the active agent, and the production method (Fig. 1.1). Nanospheres are characterized by a matrix where the drug can be bound at the surface or dissolved into it. In contrast, nanocapsules are reservoir systems composed of a membrane, and the drug is confi ned into the
inner liquid core or adsorbed at the surface (Reis et al. 2006). In this regard, many of the methodologies proposed for drug encapsulation in polymeric NPs require the presence of the drug in the reaction medium, which can lead to the inactivation of the drug, since several of these procedures use aggressive conditions, such as solvents or aggressive stirring (Reis et al. 2006). To overcome these limitations it has been proposed producing hydrogels in the absence of the drug, and then drug loading and NP formation due to the collapse of the gel.
