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31 results on '"Heras, Angeles"'

8. Contributor contact details

Author

Prokopovich, Polina, primary, Callard Preedy, Emily, additional, Prokopovich, Polina, additional, Perni, Stefano, additional, Harris, Ruth, additional, Acosta, Niuris, additional, Heras, Angeles, additional, Guzmán, Eduardo, additional, Ruano, Marta, additional, Rubio, Ramón G., additional, Ortega, Francisco, additional, Mileva, Elena, additional, Soklev, Borislav, additional, Michailova, Victoria, additional, and Arabadzhieva, Dimi, additional

Published
2013
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29. Tight junction modulation by chitosan nanoparticles: comparison with chitosan solution

Author

Vllasaliu, Driton, Exposito-Harris, Ruth, Heras, Angeles, Casettari, Luca, Garnett, Martin, Illum, Lisbeth, Stolnik, Snow, Vllasaliu, Driton, Exposito-Harris, Ruth, Heras, Angeles, Casettari, Luca, Garnett, Martin, Illum, Lisbeth, and Stolnik, Snow

Abstract

Present work investigates the potential of chitosan nanoparticles, formulated by the ionic gelation with tripolyphosphate (TPP), to open the cellular tight junctions and in doing so, improve the permeability of model macromolecules. A comparison is made with chitosan solution at equivalent concentrations. Initial work assessed cytotoxicity (through MTS and LDH assays) of chitosan nanoparticles and solutions on Calu-3 cells. Subsequently, a concentration of chitosan nanoparticles and solution exhibiting minimal toxicity was used to investigate the effect on TEER and macromolecular permeability across filter-cultured Calu-3 monolayer. Chitosan nanoparticles and solution were also tested for their effect on the distribution of the tight junction protein, zonnula occludens-1 (ZO-1). Chitosan nanoparticles produced a sharp and reversible decrease in TEER and increased the permeability of two FITC-dextrans (FDs), FD4 (MW 4. kDa) and FD10 (MW 10. kDa), with effects of a similar magnitude to chitosan solution. Chitosan nanoparticles produced changes in ZO-1 distribution similar to chitosan solution, indicating a tight junction effect. While there was no improvement in permeability with chitosan nanoparticles compared to solution, nanoparticles provide the potential for drug incorporation, and hence the possibility for providing controlled drug release and protection from enzymatic degradation.

30. Influence of Preparation Methods of Chitooligosaccharides on Their Physicochemical Properties and Their Anti-Inflammatory Effects in Mice and in RAW264.7 Macrophages.

Author

Mengíbar, María, Heras, Angeles, Acosta, Niuris, Sánchez, Ángela, Fernández, Margarita, and Alemany, Susana

Abstract

The methods to obtain chitooligosaccharides are tightly related to the physicochemical properties of the end products. Knowledge of these physicochemical characteristics is crucial to describing the biological functions of chitooligosaccharides. Chitooligosaccharides were prepared either in a single-step enzymatic hydrolysis using chitosanase, or in a two-step chemical-enzymatic hydrolysis. The hydrolyzed products obtained in the single-step preparation were composed mainly of 42% fully deacetylated oligomers plus 54% monoacetylated oligomers, and they attenuated the inflammation in lipopolysaccharide-induced mice and in RAW264.7 macrophages. However, chitooligosaccharides from the two-step preparation were composed of 50% fully deacetylated oligomers plus 27% monoacetylated oligomers and, conversely, they promoted the inflammatory response in both in vivo and in vitro models. Similar proportions of monoacetylated and deacetylated oligomers is necessary for the mixtures of chitooligosaccharides to achieve anti-inflammatory effects, and it directly depends on the preparation method to which chitosan was submitted. [ABSTRACT FROM AUTHOR]

Published
2018
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31. Calcium cross-linked carboxymethylchitosan/alginate microparticles as a system for the prolonged release of ketoprofen.

Author

Peniche, Hazel, Acosta, Niuris, Aranaz, Inmaculada, García, Lorenzo, Bada, Nancy, Heras, Angeles, and Peniche, Carlos

Subjects
*ALGINIC acid, *NONSTEROIDAL anti-inflammatory agents, *CARBOXYMETHYL compounds, *CHITOSAN, *CALCIUM chloride, *DRUG delivery systems, *ANTI-inflammatory agents
Abstract

In this work ketoprofen (KETO) loaded microparticles of carboxymethyl chitosan (CMCS) and alginate (ALG) cross-linked with CaCl2 were prepared at three compositions (CMCS-ALG 0:1, CMCS-ALG 1:2 and CMCS-ALG 1:1) to achieve the controlled release of this poorly soluble drug. CMCS with a substitution degree of 1.09 was prepared by direct alkylation of chitosan with monochloroacetic acid and isopropanol. KETO loaded microparticles were obtained by spray drying. They were characterized by infrared spectroscopy, X-ray diffraction and scanning electron microscopy. Microparticles were reticulated with 4 M CaCl2. Drug release was performed at pH 1,2 and 7,4. It was higher at pH 7,4. At this pH, CMCS-ALG 0:1microparticlesreleased almost 75 % of KETO in 20 hours whereas the other formulations released about 40 % of the drug.It is concluded that calcium cross-linked CMCS-ALG microparticles are a promising vehicle for designing a formulation for the prolonged release of KETO. [ABSTRACT FROM AUTHOR]

Published
2019

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