Micro- and mesoporous structures as drug delivery carriers for salicylic acid

The potential of salicylic acid (SA) encapsulated in porous materials as drug delivery carriers for cancer treatment was studied. Different porous structures, the microporous zeolite NaY, and the mesoporous SBA-15 and MCM-41 were used as hosts for the anti-inflammatory drug. Characterization with different techniques (FTIR, UV/vis, TGA, 1H NMR, and 13C CPMAS NMR) demonstrated the successful loading of SA into the porous hosts. The mesoporous structures showed to be very efficient to encapsulate the SA molecule. The obtained drug delivery systems (DDS) accommodated 0.74 mmol (341 mg/gZEO) in NaY and 1.07 mmol (493 mg/gZEO) to 1.23 mmol (566 mg/gZEO) for SBA-15 and MCM-41, respectively. Interactions between SA molecules and pore structures were identified. A fast and unrestricted liberation of SA at 10 min of the dissolution assay was achieved with 29.3, 46.6, and 50.1 µg/mL of SA from NaY, SBA-15, and MCM-41, respectively, in the in vitro drug release studies (PBS buffer pH 7.4, 37 °C). Kinetic modeling was used to determine the release patterns of the DDS. The porous structures and DDS were evaluated on Hs578T and MDA-MB-468 breast cancer cell lines viability. The porous structures are nontoxic to cancer cells. Cell viability reduction was only observed after the release of SA from MCM- 41 followed by SBA-15 in both breast cancer cell lines.

Modelos de negocio orientados al consumidor en los cibermedios españoles

La viabilidad de los cibermedios y los modelos de negocio que la sustenten son ya un tema  clásico  de  la  literatura  académica  y  profesional  en  el  ámbito  del  periodismo  electrónico. Consideramos relevante examinar las estrategias de ingresos orientadas al consumidor  de  los  cibermedios  españoles  en  un  contexto  de  madurez  de  la  prensa  digital que contrasta con la aguda crisis económica que vive en estos momentos el país.  Las  conclusiones  de  nuestro  estudio  señalan  la  convivencia  de  dos  modelos  de  negocio diametralmente distintos entre los cibermedios más vistos y de referencia en Internet en España y el establecimiento de estrategias de ‘suma de valor’ en aquellos cibermedios que han establecido sistemas de pago por consumo de contenidos.