β-Cyclodextrin-functionalized mesocellular silica foams as nanocarriers of doxorubicin

In this work, the preparation of inclusion complexes by functionalizing mesocellular silica foam (MCF) with beta-cyclodextrin (beta-CD) is reported. Likewise, the effect of the grafted beta-CD amount on the loading and release of doxorubicin (Dox) at simulated physiological and lysosomal pH was studied. First, MCF silica was functionalized with beta-CD under different conditions by means of reflux in toluene. The materials obtained were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). By means of TGA, the grafting percentage of beta-CD onto MCF was determined, obtaining a grafting range from 10 to 40%. The drug was loaded into the inclusion complexes by immersion in an aqueous Dox solution and then the release was studied at different pH values (7.4, 5.0) at 37 C. The results suggested that the silica materials modified with beta-CD could act as drug carriers in the sustained and directed administration of this anticancer agent, loading up to 1.17 x 10(-1) mg Dox/mg MCF-(beta-CD) in 72 h and releasing up to 70%. Kinetically, the release profiles of the inclusion complexes were better adjusted to the Higuchi model, suggesting that release was carried by diffusion of drug from the inclusion complex to the simulated pH medium.