Dissertation > Excellent graduate degree dissertation topics show

Surface Functionalization of Bimodal Mesopores Silicas and the Application in Drug Delivery

Author: GaoLin
Tutor: SunJiHong
School: Beijing University of Technology
Course: Applied Chemistry
Keywords: Dual model mesoporous SiO2 Surface functionalization Controlled release Drugs
CLC: R943
Type: PhD thesis
Year: 2011
Downloads: 257
Quote: 0
Read: Download Dissertation

Abstract

Slow release drug delivery system refers to a slow release drug delivery system in the water or a specific medium, has many advantages, including to reduce the administration frequency, improving patient compliance, to maintain a smooth and effective blood concentration, and improve drug safety and efficacy, and to reduce the adverse effects of drugs on the gastrointestinal tract, more and more people's attention. The initial drug release system is non-degradable, and then gradually be biodegradable polymer substituted, In recent years, with the development of nanotechnology, many organic nanomaterials are as drug carriers has been widely studied. Despite the advantage of nano-materials as drug carriers biological degradation is no doubt, but because of the poor chemical stability of the organic material, the release rate of poor controllability, compatibility is not ideal, and so obviously insufficient inorganic nanomaterials in recent years in the pharmaceutical aspects of the slow controlled release more and more attention. With the emergence of the M41S mesoporous nanomaterials in 1992, scientists have noted that this new type of inorganic nano-pore material can overcome these deficiencies, to become one of the more excellent performance carrier. Since the 2001 Professor Spain Vallet-Regí first reported application mediated hole nano material MCM-41 mesoporous nanomaterials as ibuprofen vector, as compared with the other nanomaterial Because of its excellent structural properties, e.g. pore surface sufficient silanols enough active sites for drug loading; the mesopores regulation for different drug molecules to \occupies an important position. The double model mesoporous materials (BMMs) is a novel mesoporous material, it has a double-hole channel structure: the Wormlike a hole 3 nm and the stacking holes of the spherical particles of about 10-30 nm. BMMs different from those of a single pore mesoporous materials having many of the unique nature of the controlled structure and granularity controllable by further surface modification, it is possible for a specific drug molecule, especially insoluble drug molecules loaded with controlled release, having good specificity. Can be achieved in the simulated body environment and MCM-41 and SBA-15 compared to the slow controlled release of a variety of drugs, a good carrier for controlled drug release. Main preparation BMMs, through two silane coupling agent 3 - aminopropyl triethoxysilane, or 3 - (2 - aminoethyl amino) propyl trimethoxysilane its surface functional process as aspirin, ibuprofen and paclitaxel carrier, MCM-41 and SBA-15 as a comparison study mesoporous pore structure, surface properties, as well as the release medium molecular size, solubility controlled release of different drugs law. Application Korsmeyer-Peppas equation release kinetic constants k study drug release process, combined with the density functional theory, Flynn-Wall-Ozawa and Kissinger methods to study the surface energy of the mesoporous surface amino modified release drug loading process changes in the law, as well as the apparent activation energy, thereby influencing factors and control mechanisms of the slow release of mesoporous materials. First, for the sparingly water-soluble small molecule drugs aspirin, compared with MCM-41 and SBA-15, BMMs having two holes structure, although the loading is less than with larger mesopores of SBA-15, but can be in a larger drug loading based on the amount to achieve a better slow release; BMMs the surface energy of which is conducive to interaction with aspirin molecules can be improved by changing the type and quantity of the BMMs surface functional groups, to achieve a high drug loading. Therefore choose a different pore structure of the mesoporous material and the application of different functional groups on the surface of the mesoporous modification is an effective means for control of drug loading and release. As molecular size increases on the basis of the above conclusions, the insoluble drug ibuprofen, hindered multilayer physical adsorption of the drug and therefore the BMMs loading greater than SBA-15; obtained by changing the particle size at the same time having a different two level accumulation of holes BMMs applied to the slow release of ibuprofen, studies have shown that the functional groups and the drug molecules into a hole in the 3 nm, while the size of the particle packing bore a direct impact on the diffusion behavior of drug molecules, thus increasing the BMMs The particle size can improve the ibuprofen release rate; addition seen based on the interaction between the drug molecules with the surface an organic group, during the release of desorbed by the surface of the mesoporous ibuprofen ion state exists, therefore simulated body fluid and compared to the simulated gastric fluid, with water as release medium beneficial to the ionic state of the release of ibuprofen; opposite hindered, ibuprofen molecule is insoluble in water, in the release of the acidic simulated gastric fluid molecular ibuprofen release rate low, indicating that the release medium pH and composition will also affect drug release performance. When the the BMMs application for the natural product taxol carrier, since paclitaxel greater molecular size, and does not dissolve in water, in the loading process is mainly adsorbed on the opening portion of mesoporous described mesoporous aperture in addition would affect the diffusion behavior of the drug molecule, drug size restrictions also obvious; taxol molecular non-polar, when the surface of the nano-materials grafted polar aminopropyl, taxol loading is significantly reduced, once again verify the interaction of the drug molecules with the surface functional groups achieve drug loading important factors. In addition preliminary exploration BMMs paclitaxel drug carrier in the water release properties of, discovered BMMs as taxol carrier able to achieve drug release, but control of the rate of release is for further study. Application of a variety of characterization methods, such as X-ray diffraction, high-resolution scanning electron microscopy, transmission electron microscopy, nitrogen adsorption - desorption, thermal gravimetric analysis, solid-state silicon NMR, elemental analysis, IR and UV spectra of functionalized mesoporous material after processing, and the drug loading and release characterization. Mesoporous nanomaterials drug release model based on the above proposed as a practical application of the drug release carrier to provide a reliable experimental basis by density functional theory and thermal decomposition kinetics from the microscopic level to explore mesoporous materials as drug carriers in the mechanism of action of the drug loading and release process.

Surface Functionalization of Bimodal Mesopores Silicas and the Application in Drug Delivery

Abstract

Related Dissertations