Hybrid mesoporous silica with controlled drug release

Abstract

The mesoporous silica particles were prepared by the sol-gel method in one-step synthesis, in acidic conditions, from tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES), varying the mole ratio of the silica precursors. Nitric acid was used as catalyst at room temperature and hexadecyltrimethyl ammonium bromide (CTAB) as structure directing agent. Optical properties, porosity and microstructure of the materials in function of the MTES/TEOS ratio were evaluated using infrared spectroscopy, nitrogen adsorption and small angle X-ray scattering. All materials showed the ordered pore structure and the high specific surfaces, making them suitable as the drug delivery systems. Drug loading and release tests using ketoprofen were performed to assess their performance for drug delivery applications. The amount of the methylated precursor used in the synthesis had little effect on the drug loading capacity, but had a strong influence on the initial rate of the drug release.

Comparison of Structure and Adsorption Properties of Mesoporous Silica Functionalized with Aminopropyl Groups by the Co-Condensation and the Post Grafting Methods

“…This shows that the increase of the amount of organic silica precursor in the co-condensation leads to the decrease of the long-range ordering of the parallel channels. Such decrease of the ordered porosity has been found for composite MCM-41 prepared using a mixture of TEOS and methyl-triethoxysilane precursors, both in acidic and alkaline conditions [ 38 , 45 , 46 , 47 ]. Calcination at 550 °C caused a shrinkage of the unit cell dimension by 6%, as commonly observed in ordered mesoporous silica prepared with CTAB [ 43 , 45 ].…”

“…The FT-IR spectra, shown in Figure 1 , reveal the characteristic bands for the aminopropyl functionalized silica materials. All samples show the specific vibration bands assigned to the silica skeleton at 1050, 800, and 450 cm −1 , corresponding to the asymmetric stretching, symmetric stretching, and bending vibration of the Si-O-Si network, respectively [ 38 ]. The presence of the silanol groups were confirmed by the existence of the band centered about 960 cm −1 , which is associated with the stretching mode of the Si-OH groups [ 39 ].…”

Heterogeneous catalyzed isomerization of turpentine oil by ordered mesoporous materials like M41S structures

“…The reaction solution provided by the mixture of all components is followed by its gelation, whereas the surfactant micelles present in the solution are subsequently coated with condensing silica. [ 40 ] This procedure is known as the sol–gel method and requires a hydrothermal treatment at a high temperature and a long reaction time to obtain an ordered pore arrangement and a stable solid phase. Next, the organic phase present in the pores must be removed by a calcination treatment.…”