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Purpose. To assess the potential of chitosan (CS) nanoparticles for ocular drug delivery by investigating their interaction with the ocular mucosa in vivo and also their toxicity in conjunctival cell cultures. Methods. Fluorescent (CS-fl) nanoparticles were prepared by ionotropic gelation. The stability of the particles in the presence of lysozyme was investigated by determining the size and their interaction with mucin, by measuring the viscosity of the mucin dispersion. The in vivo interaction of CS-fl nanoparticles with the rabbit cornea and conjunctiva was analyzed by spectrofluorimetry and confocal microscopy. Their potential toxicity was assessed in a human conjunctival cell line by determining cell survival and viability. Results. CS-fl nanoparticles were stable upon incubation with lysozyme and did not affect the viscosity of a mucin dispersion. In vivo studies showed that the amounts of CS-fl in cornea and conjunctiva were significantly higher for CS-fl nanoparticles than for a control CS-fl solution, these amounts being fairly constant for up to 24 h. Confocal studies suggest that nanoparticles penetrate into the corneal and conjunctival epithelia. Cell survival at 24 h after incubation with CS nanoparticles was high and the viability of the recovered cells was near 100%. Conclusions. CS nanoparticles are promising vehicles for ocular drug delivery.

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Please cite this article in press as: Zorzi, G., et al. On the use of nanotechnology-based strategies for association of complexes matrices from plant extracts. Revista Brasileira de Farmacognosia (2015), http://dx.BJP 159 1-11 Revista Brasileira de Farmacognosia xxx (2015) xxx-xxx w w w . s b f g n o s i a . o r g . b r / r e v i s t a a b s t r a c tDepending on the method of extraction, plant extracts can contain an enormous variety of active molecules, such as phenolic compounds, essential oils, alkaloids, among others. In many cases, from a pharmacological point of view, it is interesting to work with crude extract or fractions instead of a single isolated compound. This could be due to multi-targeting effect of the extract, lack of knowledge of the active compounds, synergistic effect of the extract compounds, among others. In any case, in order to achieve a final product some issues must be overcome, including poor stability, solvent toxicity, and low solubility of the bioactive compound. Recently many nanotechnology-based strategies have been proposed as an alternative to solve these problems, especially liposomes, nanoemulsions and nanoparticles. In this sense, the present work aims to review the main nanotechnological approaches used for association of different plant extracts and the main achievements form using these technologies.