Preparation Of Mesoporous Hollow Material And Its Application In Sustained Release Of Drugs

In recent decades,with the improvement of medical standards,people have put forward higher requirements for drug treatment.Therefore,some drugs with poor water solubility have developed drug sustained-release technology,which can achieve better therapeutic effect by loading the drug on the carrier and releasing it slowly.Among them,mesoporous hollow silica is one of the most ideal carriers.It not only has the advantages of traditional mesoporous silica materials,but also has a unique hollow structure which makes its smaller and capacity larger.However,the research on mesoporous hollow materials focuses on how to improve the specific surface area and adjust the pore structure,and few studies have been done on improving the silicon hydroxyl group on the material surface,increasing the adhesion ability of the material surface and shortening the synthesis time of the material.Therefore,a kind of mesoporous hollow silica with rough surface and rich silicon hydroxyl was synthesized by using nanocellulose as template,and a kind of "cauliflower like" double shell mesoporous hollow material was rapidly synthesized by using resorcinol and formaldehyde as template.The adsorption of drugs on these materials was calculated by quantum chemistry.(1)Mesoporous hollow silica materials with different morphologies were synthesized by micellar epitaxial growth using nano cellulose as template in the oil /water interface system.The surface of the materials has silica nanotubes formed by micelles,which is similar to the surface of viruses,extremely rough and not smooth.Through the investigation of temperature,pH,stirring speed and reaction time,rod likemesoporous silica and durian like mesoporous silica were synthesized under different conditions.By the characterization of the transmission electron microscope(TEM),scanning electron microscope(SEM),nitrogen adsorption desorption,infrared spectrum,solid 29 Si CP / MAS,the results show that the mesoporous hollow silica materials synthesized by using nanocellulose as template have good specific surface area,pore volume and pore size,unique surface roughness structure and rich silicon hydroxyl content,especially with significantly more geminal silicon hydroxyl sites,which is conducive to the growth of sustained-release time and the improvement of bacterial adhesion.(2)Three kinds of drugs with different molecular size and solubility were used as models,which were ibuprofen,aspirin and lysozyme.Through drug loading and slow-release,it was found that the synthesized mesoporous hollow materials had better drug loading and slow-release ability for all three drugs,and the rod-shaped mesoporous hollow materials had better effect,and the loading capacity for two small molecular drugs,such as ibuprofen and aspirin,was better.The loading of lysozyme is large,while the time of release is longer than that of two kinds of small molecule drug,which is closely related to the force and molecular size between materials and drugs.Compared with other three kinds of mesoporous materials,such as smooth mesoporous silica hollow spheres,MCM-41 and SBA-15,the results showed that the slow-release time of the synthesized surface rough mesoporous silica hollow materials was longer,which was consistent with the rich silicon hydroxy group.At the same time,the rough materials had better antibacterial ability.(3)The cauliflower like double shell mesoporous hollow silica nanoparticles were synthesized by the condensation of formaldehyde with resorcinol as template and tetraethyl orthosilicate as silicon source.The effects of temperature and reaction time were investigated in detail,and the best synthesis process was obtained: reaction temperature 50 ?,the amount of silicon added twice 9 mL each,and the time interval of second coating 2 h.The structure and properties were characterized by transmission electron microscopy(TEM),scanning electron microscopy(SEM),N2 adsorption desorption and X-ray diffraction(XRD).The results show that the material has a typical double shell structure and a cauliflower like surface.Compared with most of the modified St?ber method,the synthesis method has shorter time and higherefficiency.And the material is used in drug loading and sustained-release and found that the material has better drug loading and sustained-release performance.(4)Based on the model of different silicon hydroxyl types and drug molecules,further through the structure optimization,electrostatic potential(ESP)analysis,reduced density gradient(RDG)analysis,the calculation and comparison of interaction energy,it is found that the adsorption of silicon hydroxyl to the two drugs is mainly driven by hydrogen bond and van der Waals force,and geminal silicon hydroxyl has more interaction with the two drugs than single silicon hydroxyl.And the interaction energy of ibuprofen is greater than that of aspirin,which shows that geminal silicon hydroxyl is more favorable for adsorption and special for ibuprofen adsorption.This is consistent with the results of drug loading and sustained-release of the surface rough mesoporous hollow materials with high hydroxyl content(geminal siohydroxyl and and single silicohydroxyl)synthesized with nanocellulose as template.