Drug delivery is an important field of nanomedicine, and its aim is to deliver specific active substances to a precise site of action in order to produce a desired pharmacological effect. In the present study nanocapsules were obtained by a process of interfacial condensation between chitosan (dissolved in the aqueous phase) and poly(N-vinyl pyrrolidone-alt-itaconic anhydride), a highly reactive copolymer capable of easily opening the anhydride ring under the action of amine groups of chitosan. The formed amide bonds led to the formation of a hydrogel membrane. The morphology of the obtained nanocapsules, their behavior in aqueous solution of physiological pH, and their ability to encapsulate and release a model drug can be modulated by the parameters of the synthesis process, such as the molar ratio between functional groups of polymers and the ratio of the phases in which the polymers are solubilized. Although a priori both polymers are biocompatible, this paper reports the results of a very detailed in vivo study conducted on experimental animals which have received the obtained nanocapsules by three administration routes—intraperitoneal, subcutaneous, and oral. The organs taken from the animals’ kidney, liver, spleen, and lung and analyzed histologically demonstrated the ability of nanocapsules to stimulate the monocytic macrophage system without producing inflammatory changes. Moreover, their in vivo behavior has been shown to depend not only on the route of administration but also on the interaction with the cells of the organs with which they come into contact. The results clearly argue the biocompatibility of nanocapsules and hence the possibility of their safe use in biomedical applications.

Cancer remains one of the world’s most devastating diseases and is responsible for more than 20% of all deaths. It is defined as uncontrolled proliferation of cells and spreads rapidly to healthy tissue. Controlled drug delivery systems offers great opportunities for the development of new non-invasive strategies for the treatment of cancers. The main advantage of these systems is their capacity to accumulate in tumors via enhanced permeability and retention effects. In the present study, an innovative hybrid drug delivery system based on nanocapsules obtained from the interfacial condensation between chitosan and poly(N-vinyl pyrrolidone-alt-itaconic anhydride) and containing both magnetic nanoparticles and an antitumoral drug was developed in order to improve the efficiency of the antitumoral treatment. Using dynamic light scattering, it was observed that the mean diameter of these hybrid nanocapsules was in the range of 43 to 142 nm. SEM confirmed their nanometric size and their well-defined spherical shape. These nanocapsules allowed the encapsulation of an increased amount of 5-fluorouracil and provided controlled drug release. In vitro studies have revealed that these drug-loaded hybrid nanocapsules were able to induce a cytostatic effect on breast carcinoma MCF-7 cell lines (Human Caucasian breast adenocarcinoma - HTB-22) comparable to that of the free drug.