Advanced Drug Delivery Vectors with Tailored Surface Properties Made of Mesoporous Binary Oxides Submicronic Spheres

The Synthesis of mesoporous silica-zirconia mixed oxides that can be used as efficient drug delivery carriers for bisphosphonates based drugs has been performed via spray-drying process. These silica-zirconia mixed oxides used for the first time as drug delivery systems exhibit mesostructures with tunable acidity. The two selected drugs were alendronate and zoledronate, which carry similar phophonate heads but different amine tails in terms of acidity and hydrophobicity. The incorporation of different zirconium amounts into the mesostructured silica network creates Lewis and Bronsted acid surface sites allowing to control the surface properties of the mesoporous matrix and therefore the amount of phosphonate adsorbed into the mesopores. This effect occurs even at low ZrO2 contents and produces a noticeable modification on the release behavior of bisphosphonates. The patients retention of the drug through phosphonates complexation by zirconium sites leads to a more sustained release of the drug. These binary ordered mesoporous oxides act as versatile controlled release vectors of bisphophonates with potential application in bone implant technologies. This novel application of these silica-zirconia oxides and their capability to tune the drug release kinetics augur a significant advance in the field of materials science.