Correlating Surface-Functionalization of Mesoporous Silica with Adsorption and Release of Pharmaceutical Guest Species

Abstract

We present here a detailed molecular-level understanding of the interactions among surface-functionalized mesoporous SBA-15 silica and pharmaceutical guests that influence macroscopic adsorption and release behaviors. A model drug species, methylprednisolone sodium succinate, was adsorbed on the surfaces of functionalized mesoporous SBA-15 silica materials with different aminoalkyl species and without or with C60 fullerene moieties. Zeta potential measurements show that the electrostatic interactions among methylprednisolone species and modified silica surfaces are important for the adsorption and release of the methylprednisolone molecules. Complementary one and two-dimensional (2D) solid-state 13C­{1H} NMR measurements provide evidence for specific intermolecular interactions between adsorbed methylprednisolone species and different types of functionalized silica surfaces. In particular, correlated 13C and 1H signal intensities from the methylprednisolone alkyl moieties and the aminoalkyl groups of the functionalized silica surfaces unambiguously establish their close (<1 nm) molecular proximities and strong interactions. The molecular-level insights are correlated with macroscopic adsorption and release behaviors of methylprednisolone, providing detailed new understanding of the interactions responsible for the high loadings and slow release of this important pharmaceutical agent from surface-functionalized mesoporous materials.

Modification of the Release of Poorly Soluble Sulindac with the APTES-Modified SBA-15 Mesoporous Silica

“…What was noteworthy was that none of the analyzed conditions had allowed a complete release of the drug from the carriers. This could be due to the potential diffusion resistances or the sorption equilibrium of sulindac with the modified silica surfaces [ 48 ].…”

New Drug‐Structure‐Directing Agent Concept: Inherent Pharmacological Activity Combined with Templating Solid and Hollow‐Shell Mesostructured Silica Nanoparticles

“…Regarding in vitro experiments we have concluded from previous investigations dealing with adsorption and release of pharmaceutical guest species that there are three levels of interactions among the DSDA, mesoporous SBA‐15 silica surface and the simulated external body fluid: hydrogen‐bonding and electrostatic interactions among the carboxyl groups of DSDA and APS species, and the hydrophobic–hydrophilic interactions between the DSDA and the external body fluid, establishing a DSDA concentration equilibrium between the inside of the MSNs nanoparticles where the DSDA concentration is very high and the external body fluid with a lower DSDA concentration. The question is more complicated to be answered in a biological system.…”

l-Dopa release from mesoporous silica nanoparticles engineered through the concept of drug-structure-directing agents for Parkinson's disease

“…Also, the particles can be engineered to control the pore size for the slow and sustained release of drugs. Moreover, the easy functionalization of their surface allows for the targeting of specific sites [10][11][12][13][14][15] . For certain treatments this is preferable to other conventional drug administration techniques (oral or intravenous) which result in frequent, short-term doses, which fluctuate and results in the need for large doses 16 .…”