Polymeric nanoparticles (NPs) are particles within the size range from 1 to 1000 nm and can be loaded with active compounds entrapped within or surface-adsorbed onto the polymeric core. The term “nanoparticle” stands for both nanocapsules and nanospheres, which are distinguished by the morphological structure. Polymeric NPs have shown great potential for targeted delivery of drugs for the treatment of several diseases. In this review, we discuss the most commonly used methods for the production and characterization of polymeric NPs, the association efficiency of the active compound to the polymeric core, and the in vitro release mechanisms. As the safety of nanoparticles is a high priority, we also discuss the toxicology and ecotoxicology of nanoparticles to humans and to the environment.

Cr-based coatings were prepared by cathode arc evaporation technology using N 2 and C 2 H 2 as reactive gases. Three compositions were investigated, Cr 60 N 40 , Cr 41 N 27 C 32 and Cr 67 C 33 .The present investigation is centred on the structural stability via coatings tempering up to 1000ºC, by in situ X-ray diffraction in inert atmosphere. As-deposited coatings present low order structure with a medium feature size less then 10 nm. The hexagonal β-Cr 2 N phase, characteristic of binary Cr 60 N 40 coating, was stable up to 900ºC, before recrystallization and grain growth takes place. For Cr 41 N 27 C 32 film the phase transition varies from the metastable δ-Cr(N,C) to orthorhombic chromium carbonitride Cr 3 (C x N 1-x ) 2 phase up to 800ºC and then to chromium carbide phase. No chromium nitride phases were detected in spite of the similar N and C contents after the deposition. The Cr-C coating recrystallizes into a mixture of carbide phases, mainly Cr 3 C 2 and Cr 23 C 6 after 1000ºC annealing treatment.