Sub-micron o/w emulsions coated with chitosan have been used for drug delivery, quorum sensing inhibition and vaccine development. To study interactions with biological systems, nanocapsules have been fluorescently labelled in previous works, but it is often difficult to distinguish the released label from intact nanocapsules. In this study, we present advanced labelling strategies based on FRET measurements for chitosan-coated nanocapsules and investigate their dissolution and degradation. We used FRET measurements of nanocapsules loaded with equimolar concentrations of two fluorescent dyes in their oily core and correlated them with DLS count rate measurement and absorbance measurements during their disintegration by dissolution. Using count rate measurements, we also investigated the enzymatic degradation of nanocapsules using pancreatin and how protein corona formation influences their degradation. Of note, nanocapsules dissolved in ethanol, where FRET decreased simultaneously with count rate, and absorbance caused by nanocapsule turbidity, indicating increased distance between dye molecules after their release. Nanocapsules were degradable by pancreatin in a dose dependent manner, and showed a delayed enzymatic degradation after protein corona formation. We present here novel labelling strategies for nanocapsules that allow us to judge their status and an in vitro method to study nanocapsule degradation and the influence of surface characteristics.

Introduction: Diclofenac is the most prescribed non-steroidal anti-inflammatory drug worldwide and used to reliev pain and inflammation for inflammatory arthritis. Diclofenac do not slows disease progression and cartialge damage of Rheuamtoid Arthritis individuals. Moreover, it associated with seriuos adverse effects even using regular dose regimens. Drug delivery systems can overcome this issues reducing adverse effects and optmizing efficacy. Objectives: to evaluate the activity of a lipid-core nanocapsule loaded of Diclofenac (DIC-LNC) in an experimental model of adjuvant-induced arthritis and its anti-arthritic properties at the joint components. Methods: The diclofenac nanoformulation was obtained by self-assembling methodology. The stereology analysis aproach was applied for morphological quantification of the volume, density and cellular profile count of the metatarsophalangeal joints of rats induced to adjuvant arthritis. Proinflamatory cytokines and biochemical profile was also obtained. Results: DIC-LNC is able to reduce arthitis compared to control group (p<0.0001) and DIC group (p=0.009). The TNF and IL1 cytokine as well as C-reative protein and Xanthine-oxidade were efficiently reduced by DIC-LNC. Additionally, DIC-LNC reduces synovites and condrocytes lossing compared to DIC (p<0.05)and control group (p<0.05). The synovial space volume was higher for DIC-LNC compared to DIC (p<0.05) and Control (p<0.05). These data are suggesting that DIC-LNC is showing anti-arthritic actvity preserving deep joint components. Conclusion: DIC-LNC is a promissing nanoformulation for clinical use, since is able to reduce joint inflamation and synovits, avoiding damage of cartilage and synovial space at advjuvant athrits. Further studies and developments are necessary to achieve future clinical use.

Drug delivery to the brain represents a challenge especially in the therapy of central nervous system malignancies. Simvastatin (SVT), as other statins, has shown potential anticancer properties that are difficult to exploit in the CNS. In the present work the physico-chemical, mucoadhesive and permeability enhancing properties of simvastatin-loaded poly-ε-caprolactone nanocapsules coated with chitosan for nose-to-brain administration were investigated. Lipid-core nanocapsules coated with different molecular weight (MW) chitosans (LNCchit) prepared by a novel one-pot technique were characterized for particle size, surface charge, particle number density, morphology, drug encapsulation efficiency, interaction between surface nanocapsules with mucin, drug release and permeability across two nasal mucosa models. Results show that all formulations present adequate particle size (below 220 nm), positive surface charge, narrow droplet size distribution (PDI<0.2) and high encapsulation efficiency. Nanocapsules presented controlled drug release and mucoadhesive properties dependent on the MW of the coating chitosan. The results of permeation across RPMI 2650 human nasal cell line evidenced that LNCchit increased the permeation of SVT. In particular, the amount of SVT permeated after 4h for nanocapsules coated with low MW chitosan, high MW chitosan and control SVT was 13.91 ± 0.78 µg, 9.15 ± 1.23 µg and 1.42 ± 0.21 µg respectively. These results were confirmed by the SVT ex vivo permeation across rabbit nasal mucosa. This study highlighted the suitability of LNCchit as promising strategy for the administration of simvastatin for a nose-to-brain approach for the therapy of brain tumors.