Person:
Pérez Velilla, Eduardo

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First Name
Eduardo
Last Name
Pérez Velilla
URI
https://hdl.handle.net/20.500.14352/76259
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Química Física
Area
Química Física
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    Supercritical fluid impregnation of naproxen into mesoporous SiO2 SBA-15
    (Journal of CO2 utilization, 2023) González, Juan; Pérez Velilla, Eduardo; Pepczynska, Marzena; Calvo Garrido, María Lourdes; Cabañas Poveda, Albertina
    Naproxen was impregnated into mesoporous SiO2 SBA-15 using the Supercritical Solution Impregnation (SSI) technique. Experiments were performed at 50–70ºC and 15–25 MPa in pure CO2 and CO2 modified with ethanol, ethyl acetate and menthol. Materials were also impregnated from liquid solutions in ethanol and chloroform. In the SSI experiments, naproxen was deposited on the internal surface of the mesopores as shown by N2-adsorption experiments. The percentage of naproxen impregnated decreased from 11.1% to 7.4% mass as the CO2 density increased. Likewise, adding ethanol, ethyl acetate or menthol to CO2 decreased the percentage of naproxen adsorbed on the support. Thermal analysis showed that naproxen impregnated on SiO2 by SSI became amorphous. FTIR and XRD confirmed the loss of crystallinity of naproxen and its interaction with the SiO2 support. Samples impregnated in liquid medium however kept partially their crystallinity. Release tests of naproxen on SiO2 SBA-15 prepared by SSI followed an almost zero-order release profile; the drug is released at a constant rate into a PBS pH= 7.4 medium. The release rate slowed down in comparison to that of pure naproxen, due to the interaction of the drug with the support and the diffusion of the drug outside the support mesopores. Thus, a sustained release system was achieved, which may help to attain a longer therapeutic effect with a lower naproxen dose.
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    Phase equilibria for the mixtures of the deep eutectic solvent L-menthol + thymol plus CO2 at high pressure
    (Journal of Industrial and Engineering Chemistry, 2023) Pérez Velilla, Eduardo; Rato, Sergio; Loaisa, Gema; Cabañas Poveda, Albertina
    The Vapour-Liquid Equilibrium (VLE) of different mixtures of CO2 + L-menthol, CO2 + thymol and CO2 + L-menthol + thymol has been determined at 35, 40, 50 and 60 °C and pressures up to 220 bar using a variable volume view cell. Menthol + Thymol form a deep eutectic solvent (DES) mixture at a 1:1 molar ratio. For selected conditions, the composition of the vapour phase was determined by 1H NMR. By interpolation of the experimental values, ternary diagrams were built. The mutual solubility between CO2 and DES decreased as the proportion menthol:thymol approached the eutectic composition (1:1). Mutual miscibility also decreased with temperature and increased with pressure. The composition of the mixture of menthol + thymol (1:1) does not remain stable at 60 °C but it does at lower temperatures. The intermolecular interactions between menthol and thymol are responsible for this behaviour. The Peng-Robinson equation of state was used to correlate the results with promising results.