Hybrid Organic–Inorganic Biomaterials as Drug Delivery Systems: A Molecular Dynamics Study of Quercetin Adsorption on Amorphous Silica Surfaces

Many important drugs in pharmaceutical applications are poorly soluble. Solubilization, which is diffusion through biological barriers, and the control of local administration are crucial steps for bioavailability and to avoid cytotoxic effects. Hybrid organic/inorganic biomaterials can incorporate drugs for in situ release after implantation. Molecular Mechanics (MM) and Molecular Dynamics (MD) simulations are useful tools for investigating intermolecular interactions between drug and biomaterial surfaces at the atomistic level for these applications. This work studies quercetin, a flavonoid drug important for its anti-inflammatory, antioxidant, and anticancer properties, and the amorphous SiO2 surface using a simulation protocol proposed in previous work related to ketoprofen drugs. After adsorption on the amorphous silica surface, the adsorption process of quercetin drug molecules at two different drug concentrations near a hydrated and then dried silica surface is investigated. Interestingly, these theoretical results are compared with experimental data obtained via Fourier Transform Infrared Spectroscopy (FT-IR) spectra related to quercetin molecules homogenously entrapped in a silica matrix obtained via the Sol-Gel method. Favorable H- bonds and some pi-pi interactions among drug molecules are crucial surface interactions for the new generation of biocompatible materials capable of incorporating anti-inflammatory agents for release into the human body.