Browsing by Author "Duran-Lara, Esteban F."

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    Comparative Study of Three Dyes' Adsorption onto Activated Carbon from Chenopodium quinoa Willd and Quillaja saponaria
    (2022) Abril, Diana; Ferrer, Victor; Mirabal-Gallardo, Yaneris; Cabrera-Barjas, Gustavo; Segura, Cristina; Marican, Adolfo; Pereira, Alfredo; Duran-Lara, Esteban F.; Valdes, Oscar
    The present study shows porous activated carbon obtained from Chenopodium quinoa Willd and Quillaja saponaria and their use as potential adsorbents to remove three types of dyes from aqueous solutions. The adsorption results were compared with commercial charcoal to check their efficiency. All porous carbon materials were activated using carbon dioxide and steam and fully characterized. Moreover, the steam-activated samples exhibited a high total pore volume with a BET surface area of around 800 m(2) g(-1). Batch adsorption experiments showed that commercial charcoal is the charcoal that offered the best adsorption efficiency for tartrazine and sunset yellow FCF. However, in the case of crystal violet, all activated carbons obtained from Chenopodium quinoa Willd and Quillaja saponaria showed the best captures, outperforming commercial charcoal. Molecular dockings of the dyes on the commercial charcoal surface were performed using AutoDock Vina. The kinetic results of the three isotherm's models for the present data follow the order: Langmuir similar to Freundlich > Temkin.
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    Effect of cellulose nanofibrils on vancomycin drug release from chitosan nanocomposite films
    (2023) Cabrera-Barjas, Gustavo; Becheran, Liliam; Valdes, Oscar; Giordano, Ady; Segura-del Rio, Rodrigo; Bravo-Arrepol, Gaston; Duran-Lara, Esteban F.; Cea, Juan; Berg, Alex; Castanos, Johana; Rodriguez-Llamazares, Saddys; Fuentes, Gaston; Katsarov, Plamen; Lukova, Paolina; Delattre, Cedric
    Overuse of antibiotic drugs usually leads to the further development of resistance to targeted bacteria. In this context, a controlled release system could be a solution to achieve higher drug efficiency without overdosing and drug resistance. In this work, nanocomposite films based on chitosan (CHI) reinforced with cellulose nanofibrils (CNF) for antibiotic release were prepared and characterized. Several nanocomposite films containing vancomycin hydrochloride and different amounts of CNF (5, 10, and 20 wt%) were prepared by the solvent casting method. Spectroscopic (FTIR), thermal (TG), morphological (SEM), mechanical, and swelling analyses of the films were performed to study the effect of nanofibers content on the nanocomposite properties. A good dispersion of CNF and the model drug was observed in the CHI matrix. FTIR spectroscopy confirmed the interaction between the film components (CNF and CHI). Film swelling capacity decreased with an increase of CNF content in the film formulation, whereas stiffness and tensile strength of the film increased. In addition, vancomycin release at pH = 7.4 was studied, and it was observed that controlled slower release could be achieved by tuning the CNF content in the chitosan film. The results confirm that these films could be useful for pharmaceutical purposes where the controlled release of drugs is required.