Pore Length Effect on Drug Uptake and Delivery by Mesoporous Silicas

The capability of UVM‐7 silicas to work as supports for drug storage and delivery is investigated using ibuprofen as a model. UVM‐7 silicas are surfactant‐assisted synthesised mesoporous materials displaying a characteristic bimodal pore architecture related to their nanoparticulate texture. Strict control of the drug‐charge protocol allows the achievement of high ibuprofen loads, not only because of the availability of intra‐nanoparticle mesopores and large textural voids, but also owing to the decrease in pore‐blocking effects (with regard to related unimodal mesoporous materials such as MCM‐41) achieved through the shortening of the mesopore length. The UVM‐7/ibuprofen nanocomposites are characterised using XRD, TEM and N2 adsorption/desorption isotherms, and the drug‐delivery processes are monitored by spectrometric techniques. The bimodal porosity results in two‐stage drug‐delivery processes, which are analysed through kinetic models. Short is better: The advantages of using mesoporous supports for drug supply depend on the feasibility of mass transfer through confined spaces, which is clearly improved by short‐length mesopores insofar as the undesirable effects associated with blocking phenomena are greatly reduced (see figure).