Comparative In Vitro Study between Biocompatible Chitosan-Based Magnetic Nanocapsules and Liposome Formulations with Potential Application in Anti-Inflammatory Therapy.

This study describes the comparison between the interaction of a series of peptide-functionalized chitosan-based nanocapsules and liposomes with two cell lines, i.e., mouse macrophages RAW 264.7 and human endothelial cells EA.hy926. Both types of nanocarriers are loaded with magnetic nanoparticles and designed for anti-inflammatory therapy. The choice of these magnetic nanostructures is argued based on their advantages in terms of size, morphology, chemical composition, and the multiple possibilities of modifying their surface. Moreover, active targeting might be ensured by using an external magnetic field. To explore the impact of chitosan-based nanocapsules and liposomes on cell cytophysiology, the cell viability, using the MTT assay, and cell morphology were investigated. The results revealed low to moderate cytotoxicity of free nanocapsules and significant cytotoxicity induced by chitosan-coated liposomes loaded with dexamethasone, confirming its release from the delivery system. Thus, after 48 h of treatment with nanocapsules, the viability of RAW 264.7 cells varied between 88.18% (OCNPM-1I, 3.125 µg/mL) and 76.37% (OCNPM-1, 25 µg/mL). In the same conditions, EA.hy926 cell viability was between 99.91% (OCNPM-3, 3.125 µg/mL) and 75.15% (OCNPM-3, 25 µg/mL) at the highest dose (25 µg/mL), the values being comparable for both cell lines. Referring to the cell reactivity after dexamethasone-loaded liposome application, the lowest viability of RAW 264.7 cells was 41.25% (CLDM5CP-1, 25 µg/mL) and 58.20% (CLDMM2CP-1 1.25 µg/mL) in the endothelial cell line, proving a selective character of action of nanocarriers. The cell morphology test, performed to support and confirm the results obtained by the MTT test, revealed a differentiated response for the two types of nano-carriers. As expected, an intense cytotoxic effect in the case of dexamethasone-loaded liposomes and a lack of cytotoxicity for drug-free nanocapsules were noticed. Therefore, our study demonstrated the biocompatible feature of the studied nanocarriers, which highlights them for future research as potential drug delivery systems for pharmacological applications, including anti-inflammatory therapy.

Design and characterization of dexamethasone phosphate -loaded microcapsules obtained by a double-emulsion method.

Polymeric microcapsules are extensively investigated as drug delivery systems for a broad range of applications. In the present study, Dexamethasone-loaded carboxylated chitosan (CCS)/poly (vinyl alcohol) (PVA)-based microcapsules were prepared in view of their potential administration by inhalation for the treatment of lung diseases. The crosslinking between PVA and CCS was activated by [4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride] (DMT-MM) and the FTIR results proved the formation of ester bonds between the two polymers. The sizes of the obtained microcapsules are influenced by the ratio between the polymers but also by the concentration of the DMT-MM activator. Moreover, the amount of PVA in the system has an important influence on swelling degree, encapsulation efficiency, drug release degree, biodegradation and protein adsorption. The sample with the highest amount of PVA has the highest crosslinking density and thus the lowest swelling degree and encapsulation efficiency. However, an encapsulation degree of 61.3% was obtained for the sample MCP-6 with the lowest PVA content. The same sample showed the lowest BSA adsorption. A controlled and sustained Dexamethasone release of around 90% was observed in PBS at pH 7.4 and 37 °C during 24 h. All the obtained samples were hemocompatibles and thus can be used as efficient drug delivery systems.

Drug Release from Nanoparticles (Polymeric Nanocapsules and Liposomes) Mimed through a Multifractal Tunnelling-Type Effect.

The present study analyzes (theoretically and experimentally) a drug release process from nanoparticles (polymeric nanocapsules and liposomes). This process is functionalized on the surface with an aptamer. These types of drug release processes can also be included in cream-type formulations. The obtained cream ensures the active targeting of tumor epithelial cells, in the case of skin cancer, because it can be easily administered to the skin by spreading, thus avoiding side effects caused by the toxicity of the drug to healthy cells, increasing both patient compliance and the effectiveness of the treatment. The process of obtaining these formulations is a simple one, easy to use and highly reproductible. The theoretical model, based on the multifractal tunnel effect within the Scale Relativity Theory, considers the system as a complex one. In this model, complexity is replaced with system multifractality, quantified in physical quantities as multifractal dimensions and multifractal functions. The main advantage of this approach consists in the fact that it allows us to obtain information on system behavior at a microscopic level and to evaluate microscopic characteristics of the system, such as intrinsic transparences of the drug molecules, multifractal constants as indicators of the system's complexity, the frequency of interactions within the system and the energy ratio between potential barrier energy and the energy of drug molecules.

"In vitro" behaviour of aptamer-functionalized polymeric nanocapsules loaded with 5-fluorouracil for targeted therapy.

New type of nanocapsules based on carboxymethyl chitosan functionalized with AS1411 aptamer and poly(N-vinylpyrrolidone-alt-itaconic anhydride) loaded with 5-Fluorouracil (5-FU) were developed, with the potential to improve the treatment of cancer. Functionalization of nanocapsules with AS1411 aptamer will enhance their recognition by tumor cells, due to the interaction with nucleolin, and subsequent endocytosis. Nanocapsules were prepared by interfacial condensation method in the absence of any toxic crosslinking agents. The condensation reaction took place at the interface between the organic and aqueous phases by opening the anhydride cycles from the copolymer, under the action of the NH2 groups from mixture of chitosan/aptamer-functionalized carboxymethyl chitosan. The nanocapsules diameter varied between 100 and 267 nm as a function of the molar ratio of the polymers. SEM images have revealed that nanocapsules were spherical and presented relatively low dimensional polydispersity. Nanocapsules swelling degree was found between 1000 and 1680% in PBS solution (pH = 7.4) and they allowed the encapsulation of an important amount of 5-Fluorouracil (5-FU). The release efficiency of 5-FU was studied, the processes being controlled by the drug diffusion through the polymeric membrane, as confirmed by the theoretical analysis of the drug release. The cytotoxicity and haemolysis tests performed on the nanocapsules proved their lack of toxicity and their excellent hemocompatibility. The obtained results were encouraging, showing that these original 5-FU-loaded nanocapsules were able to induce a more pronounced cytotoxic effect on neoplastic MCF-7 cells, the occurrence of dead cells being more rapidly than in the case of free 5-FU.