ANTIOXIDANT CONTAINING CHITOSAN NANOMEDICINES FOR THE PREVENTION AND TREATMENT OF DIABETIC RETINOPATHY

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Chitosan-based nanoparticles for rosmarinic acid ocular delivery-in vitro tests

Publication . Silva, Sara; Ferreira, Domingos; Pintado, M. E.; Sarmento, Bruno

tIn this study, chitosan nanoparticles were used to encapsulate antioxidant rosmarinic acid, Salvia offici-nalis (sage) and Satureja montana (savory) extracts as rosmarinic acid natural vehicles. The nanoparticleswere prepared by ionic gelation using chitosan and sodium tripolyphosphate (TPP) in a mass ratio of7:1, at pH 5.8. Particle size distribution analysis and transmission electron microscopy (TEM) confirmedthe size ranging from 200 to 300 nm, while surface charge of nanoparticles ranged from 20 to 30 mV.Nanoparticles demonstrate to be safe without relevant cytotoxicity against retina pigment epithelium(ARPE-19) and human cornea cell line (HCE-T). The permeability study in HCE monolayer cell line showedan apparent permeability coefficient Pappof 3.41 ± 0.99 × 10−5and 3.24 ± 0.79 × 10−5cm/s for rosmarinicacid loaded chitosan nanoparticles and free in solution, respectively. In ARPE-19 monolayer cell line thePappwas 3.39 ± 0.18 × 10−5and 3.60 ± 0.05 × 10−5cm/s for rosmarinic acid loaded chitosan nanoparti-cles and free in solution, respectively. Considering the mucin interaction method, nanoparticles indicatemucoadhesive proprieties suggesting an increased retention time over the ocular mucosa after instilla-tion. These nanoparticles may be promising drug delivery systems for ocular application in oxidative eyeconditions.

2016Journal article

Open access

Development and validation method for simultaneous quantification of phenolic compounds in natural extracts and nanosystems

Publication . Silva, Sara Baptista da; Oliveira, Ana; Ferreira, Domingos; Sarmento, Bruno; Pintado, Manuela

IntroductionSage and savoury (Salvia sp. and Satureja montana, respectively) are plants used in traditional medicine. The quality control of their herbal formulations is of paramount concern to guarantee the expected biological activity of their anti-oxidant compounds. Objective To establish a simple and effective high-performance liquid chromatographic (HPLC) method to evaluate simultaneously quercetin and rosmarinic acid, in a pure form, in natural extracts (sage and savoury), and encapsulated into chitosan nanoparticles. Methods Chromatography was performed on an RP C-18-column, in a gradient mode with a mobile phase comprising methanol:formic acid:water 92.5:2.5:5 (v/v) at a flow rate of 0.75mL/min and at wavelength of 280nm. Results The method was specific, linear in the range of 0.05-1mg/mL (R-2=1.00), precise at the intraday and interday levels, accurate (recovery rate 90.50.6%), and robust to changes in equipment conditions. Conclusion The method established was effective for quercetin and rosmarinic acid characterisation in natural extracts and in chitosan nanoparticles, allowing the loading capacity determination, the association efficiency as well as the in vitro release. This study shows a new HPLC method validated to simultaneous quantification of rosmarinic acid and quercetin in natural extracts and chitosan nanoparticles. This method is also able for detection and quantification of other phenolic and flavanoid compounds in natural matrix.

2013Journal article

Restricted access