Tunability of Pore Diameter and Particle Size of Amorphous Microporous Silica for Diffusive Controlled Release of Drug Compounds

Abstract

Amorphous microporous silica (AMS) materials with variation in microporosity were prepared using an acid-catalyzed sol−gel procedure departing from tetraethylorthosilicate. The silicas were fined to specific particle sizes by crushing and sieving. AMS materials were loaded with 10 wt % ibuprofen either by uptake of molten ibuprofen or by adsorption of ibuprofen from a methylene chloride solution. DSC analysis of ibuprofen-loaded AMS confirmed the molecular dispersion of ibuprofen on the silica material. In vitro ibuprofen release from AMS carrier was investigated in simulated intestinal fluid and in a dissolution medium simulating the gastrointestinal tract with simulated gastric fluid followed by simulated intestinal fluid. The release of ibuprofen molecules from the AMS silica carrier is governed by diffusion. The diffusivity of ibuprofen in the investigated series of AMS samples was in the range 10-14−10-11 m2 s-1. By adapting the porosity and particle size of AMS, the release could be evenly spread over periods from 3 to 100 h. This flexibility of AMS opens perspectives for designing tailor-made controlled release formulations.

29Si NMR and UV−Raman Investigation of Initial Oligomerization Reaction Pathways in Acid-Catalyzed Silica Sol−Gel Chemistry

“…The silica gel materials obtained under the here described conditions are microporous with narrow monomodal pore size distribution and have been reported to be suitable for controlled release of drug molecules and antiseptic agents. [60][61][62][63][64] ' EXPERIMENTAL SECTION The sol-gel synthesis was performed at room temperature while continuously stirring with a magnetic bar. Typically, TEOS (Acros, 98%) was dissolved in ethanol (VWR, absolute grade, 99.9%).…”

Silica‐Coated Liposomes for Insulin Delivery

“…Initiation of silica growth above the surface of insulin loaded PC nanosphere occurs through hydrolysis of silica precursor at lower pH (2.5) and promotes colloidal silica formation by release of alcohol followed by silanol condensation leading to gelation. Presence of silica coating around insulin loaded PC nanosphere prevents it from denaturation due to pH and enzymes [31][32][33][34][35][36]. Insulin encapsulation within PC vesicles and silica coated PC nanosphere was studied by Confocal microscopic investigation using FITC-insulin during encapsulation.…”

Nanoporous Silica-Based Materials for Sorption of Pharmaceuticals and Biomolecules

“…C.A. Aerts and co-workers [69] examined how silica source and type of solvent influence on porous structure of final material. They tested as-obtained materials as potential sorbents for ibuprofen.…”