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

Abstract

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 π–π 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.

Effect of Nitric Acid on the Synthesis and Biological Activity of Silica–Quercetin Hybrid Materials via the Sol-Gel Route

“…The increase in the broadness of -OH stretching vibration at 3457 cm −1 is indicative of the formation of H-bonds between the hydroxyl group of the silanol group from the silica matrix and the -OH groups of entrapped quercetin. This was also demonstrated using a dynamic molecular approach [26], in which the interaction between the silica matrix and two amounts of quercetin, 5 and 15%, respectively, was simulated and discussed.…”

“…Furthermore, theoretical analyses supported our experimental outcomes, suggesting that at lower drug concentrations, flavonol is well absorbed into the SiO 2 surface with slow mobility. This facilitates the formation of abundant hydrogen bonds between quercetin molecules and the SiO 2 surface, thereby mitigating the formation of agglomerates typically observed at higher concentrations [25,26].…”

Physicochemical Characterization of Hydroxyapatite Hybrids with Meloxicam for Dissolution Rate Improvement

“…The rate and completeness of the adsorption of problematic drugs can be improved by many strategies, such as particle size reduction, use of solid dispersions or salts, micelles, liposomes or organic–inorganic hybrids [ 7 , 8 , 9 ]. These last systems possess many intriguing features that allow being applied as carriers for controlled and/or targeted drug release as well as to improve the long-term stability and storage of drugs by protecting them from unsafe environments [ 10 , 11 , 12 ]. Hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ) (HAP) is often the preferred inorganic support for DDS thanks to its biocompatibility, bioactivity, osteoconductivity and ease in bonding to living tissues and to molecules through simple adsorption [ 13 , 14 ].…”