Mesoporous silica- and silicon-based materials ... - Helda - Helsinki.fi

Abstract
New chemical entities with unfavorable water solubility properties are continuously
emerging in drug discovery. Without pharmaceutical manipulations inefficient
concentrations of these drugs in the systemic circulation are probable. Typically, in order
to be absorbed from the gastrointestinal tract, the drug has to be dissolved. Several
methods have been developed to improve the dissolution of poorly soluble drugs.
In this study, the applicability of different types of mesoporous (pore diameters
between 2 and 50 nm) silicon- and silica-based materials as pharmaceutical carriers for
poorly water soluble drugs was evaluated. Thermally oxidized and carbonized mesoporous
silicon materials, ordered mesoporous silicas MCM-41 and SBA-15, and non-treated
mesoporous silicon and silica gel were assessed in the experiments. The characteristic
properties of these materials are the narrow pore diameters and the large surface areas up
to over 900 m 2 /g. Loading of poorly water soluble drugs into these pores restricts their
crystallization, and thus, improves drug dissolution from the materials as compared to the
bulk drug molecules. In addition, the wide surface area provides possibilities for
interactions between the loaded substance and the carrier particle, allowing the
stabilization of the system. Ibuprofen, indomethacin and furosemide were selected as
poorly soluble model drugs in this study. Their solubilities are strongly pH-dependent and
the poorest (