Drug removal and release studies of mesoporous and modified silica

The synthesis, characterization and modification of mesoporous silica (MS) were carried out and, drug removal and release studies were also performed. The synthesized MS has an ordered structure with high surface area and homogeneous pore size distribution, which was then modified with a Schiff base (S) ligand. The characterization of MS and Schiff base modified MS (S-MS) was accomplished with scanning electron microscopy (SEM), nitrogen gas adsorption, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and dynamic light scattering (DLS) analyses. The adsorption of diclofenac sodium (DS) and metformin HCl (MF), which were preferred as model drugs, onto MS and S-MS, was investigated in an aqueous solution with respect to pH, the amount of adsorbent and contact time. The maximum calculated values from the pseudo-second-order model for the adsorption of MF and DS were determined as 625.5 and 675.0 mg g(-)(1) for MS and 558.5 and 765.7 mg g(-)(1) for S-MS, respectively. In addition, the hybrid structures of MS and S-MS were prepared for use in the drug release studies, and their efficiencies in releasing drugs were then investigated. The releases of DS and MF from silica hybrid structures after 4 h were determined to be at around 30% and 70%, respectively.