Interaction study between drugs and some synthetic nanoporous composites

In this work MCM-41, MCM-41/NaY and Clinoptilolite/MCM-41/NaY composites that have CTMABr (N-cethyl-N,N, and N-trimethyl Ammonium Bromide) were prepared and characterized with XRD, SEM and FT-IR. Also, incorporation of two model drugs (sulfamethoxazole and metronidazole) with these composite were considered. The drug adsorption assays showed that three composites adsorb considerable amount of drugs, in particular sulfamethoxazole which was evaluated by UV spectroscopy. The results show that we have more adsorption of sulfamethoxazole for MCM-41/NaY that there is a direct relationship exists between the amounts of surfactant per gram of composite. TGA shows that the composites are more stable thermally when the ad micelles contain sulfamethoxazole in their interior. The results of adsorption of sulfamethoxazole showed that approximately 70% of drug was released from MCM-41/NaY-sulfamethoxazole system after about 24 h.     

MCM-41负载戊二酸锌催化剂催化CO2和环氧丙烷的共聚反应

制备了MCM-41负载戊二酸锌催化剂(ZnGA/MCM-41),并采用热重分析、红外光谱和X射线衍射对催化剂进行了表征。结果表明,ZnGA与载体间存在相互作用,ZnGA能以更小的粒径均匀分散到MCM-41的表面。实验研究表明,该催化剂对于CO2与环氧丙烷(PO)共聚反应显示出较高的催化效率,并得到高分子量的聚碳酸亚丙酯(PPC);通过调节负载量和催化剂的用量,最高催化效率达到了89.5g聚合物/g ZnGA;共聚产物的红外光谱和核磁数据表明,所得共聚产物具有接近完全交替(>97.4%)的碳酸酯结构。     

Steam-assisted crystallization of TPA+-exchanged MCM-41 type mesoporous materials with thick pore walls

Hierarchical MCM-41/MFI composites were synthesized through ion-exchange of as-made MCM-41 type mesoporous materials with tetrapropylammonium bromide and subsequent steam-assisted recrystallization. The obtained samples were characterized by powder X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis, FT-IR, ¹H–¹³C CP/MAS and nitrogen adsorption–desorption. The XRD patterns show that the MCM-41/MFI composite possesses both ordered MCM-41 phase and zeolite MFI phase. SEM and TEM images indicate that the recrystallized materials retained the mesoporous characteristics and the morphology of as-made mesoporous materials without the formation of bulky zeolite, quite different from the mechanical mixture of MCM-41 and MFI structured zeolite. Among others, lower recrystallization temperature and the introduction of the titanium to the parent materials are beneficial to preserve the mesoporous structure during the recrystallization process.     

Mesoporous silica directly modified by incorporation or impregnation of some heteropolyacids: Synthesis and structural characterization

The synthesis of heteropolyacids-mesoporous silica composites was carried out in acidic media by impregnation and/or by direct incorporation of active phase. The effect of incorporation of heteropolyacids (HPAs) species into organized mesoporous silica was studied by using non-ionic and cationic surfactants. A comparison between direct incorporation of HPAs into mesoporous silica and impregnation of HPAs on mesoporous silica was done. The structure and texture of H₃PMo₁₂O₄₀ and H₄PVMo₁₁O₄₀ included on mesoporous silica were studied by XRD, SEM-EDS, FT-IR and Raman spectroscopies and BET and pore size distribution. Thermal stability was determined by thermo gravimetric analysis (TGA) and differential thermal analysis (DTA). FT-IR and Raman studies showed that HPAs anions preserved their Keggin structure after incorporation or impregnation on mesoporous silica support.     

Effects of post-synthesis treatments on the pore structure and stability of MCM-41 mesoporous silica

The effects of post-synthesis treatments on the structure and the stability of MCM-41 mesoporous material were investigated. It was found that, by adding ammonium salts and adjusting pH during the post-synthesis to alkalescently synthesized MCM-41, the regularity of the pore was improved dramatically and the stability of the mesostructure was retained; conversely, they were diminished by adding sodium salts. The results were studied by analyzing the samples using X-ray diffraction (XRD), Transmission electron microscopy (TEM), Differential Thermal Analysis–Thermal Gravimetry (DTA–TG). The change of the electrostatic surrounding and the formation of hydrogen bonds caused by different ions were confirmed to be the main factors.     

超临界CO_2中MCM-41-g-PHEMA介孔复合物的制备及性能

以甲基丙烯酸羟乙酯(HEMA)为单体,用乙烯基三乙氧基硅烷改性的介孔分子筛MCM-41为载体,偶氮二异丁腈为引发剂,在超临界二氧化碳中通过沉淀聚合,成功合成了聚甲基丙烯酸羟乙酯-二氧化硅介孔复合材料(MCM-41-gPHEMA)。考察了反应物配比、反应时间和反应压力对所制复合物形貌与产率的影响。对所合成的复合物进行红外光谱分析、比表面积、小角X射线衍射、扫描电镜、透射电镜、热重分析等表征。研究了复合物的溶胀性及在不同pH下对牛血清白蛋白(BSA)水溶液的吸附性能与吸附动力学。结果表明,MCM-41-g-PHEMA的孔径约为6.3nm,热稳定性明显提高,复合物对BSA的吸附动力学符合伪二级速率方程,最大吸附量为35mg/g。     

聚苯乙烯/纳米金刚石复合微球的制备及性能测定

以纳米金刚石为乳化剂,BPO为引发剂,利用Pickering效应成功合成得到了聚苯乙烯/纳米金刚石复合微球.XRD、TDA-DTA、TEM、BET以及FT-IR分别进行了结构表征.研究结果表明,在聚苯乙烯/纳米金刚石复合微球中,纳米金刚石晶体为立方相,聚苯乙烯为无定形态,颗粒径粒大约为40～70nm,分散较好,比较面积达到230m2/g,该复合材料具有良好热稳定性.进一步的力学系性能测定表明,随着聚苯乙烯/纳米金刚石复合微球添加应用,聚苯乙烯的拉伸强度、断裂伸长率性能得到了明显地改善,但弯曲强度性能有所下降.     

Preparation and characterization of epoxy composites filled with functionalized nano-sized MCM-41 particles

Mono-dispersed nano-sized MCM-41 (M (with template)) particles were synthesized by sol–gel reaction. The effect of interface modification on the properties of epoxy composites was investigated. Modifications were carried out either by substituting silanol groups on the surface or in the mesopore channels into amine (M-NH₂), calcinating mixture template in the mesopore channels (M(without template)), or recalcinating them at higher temperature to remove silanol groups (–OH) in the mesopore channels or on the surface (CM). Transmission electron micrograph results showed that the dispersing of MCM-41 nanoparticles was not influenced by the modification, while –NH₂ group indeed modified the mesopore channels or the surface of MCM-41 particle by using IR, XRD, and N₂ adsorption–desorption. In addition, tensile tests suggested that M-NH₂ nanoparticles could simultaneously provide epoxy matrix with strengthening and toughening effects. However, due to the different interfacial structures between the fillers and the matrix, the mechanical properties of the composites filled by M-NH₂ were much better than those of composites filled by MCM-41 (without template), MCM-41 (with mixture template), and CM.     

氟化MCM-41的制备及超声触发释药性能研究

采用微波法制备了MCM-41,并将其与NH4F反应制得氟化MCM-41(F-MCM-41),采用浸渍法将抗肿瘤药物5-氟尿嘧啶(5-FU)分别组装到MCM-41和氟化MCM-41中。采用XRD、FT-IR、低温N2吸附和TG对MCM-41、氟化MCM-41和药物组装体进行了表征,考察了常规条件和超声条件下组装体在人工模拟胃液中的药物释放行为。结果表明,药物组装体超声条件下的药物释放速率明显优于常规释放。     

Functionalization of mesoporous MCM-41 for the delivery of curcumin as an anti-inflammatory therapy

In this study, mesoporous silica nanoparticles (MSNs) composed of MCM-41 were synthesized and modified with amine groups (i.e., NH₂) to form NH_2/MCM-41, which was loaded with curcumin (CUR) to form CUR@NH₂/MCM-41 to create an efficient carriers in drug delivery systems (DDSs). The three samples (i.e., pure MCM-41, NH₂/MCM-41, and CUR@NH₂/MCM-41) were characterized using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transition electron microscopy (TEM), and a thermogravimetric analyzer (TGA). The study investigated the effect of the carrier dose, CUR concentration, pH, and contact time on the drug loading efficiency (DLE%) by adsorption. The best DLE% for MCM-41 and NH₂/MCM-41 was found to be 15.78 and 80%, respectively. This data demonstrated that the Langmuir isotherm had a greater correlation coefficient (R²) of 0.9840 for MCM-41 and 0.9666 for NH₂/MCM-41 than the Freundlich and Temkin isotherm models. A pseudo-second-order kinetic model seems to fit well with R² = 0.9741 for MCM-41 and R² = 0.9977 for NH₂/MCM-41. A phosphate buffer solution (PBS) with a pH of 7.4 was utilized to study CUR release behavior. As a result, the full release after 72 h was found to have a maximum of 74.1% and 29.95% for pure MCM-41 and NH₂/MCM-41, respectively. The first-order, Weibull, Hixson-Crowell, Korsmeyer-Peppas, and Higuchi kinetic release models were applied to releasing CUR from CUR@MCM-41 and CUR@NH₂/MCM-41. The Weibull kinetic model fit well, with R² = 0.944 and 0.96912 for pure MCM-41 and NH₂/MCM-41, respectively.     

含季铵荷电基团的有机-无机杂化介孔材料的合成与表征

以十二烷基硫酸钠(SDS)为模板剂,正硅酸乙酯(TEOS)和N-三甲氧基硅丙基-N,N,N-三甲基氯化铵(TSPMNC)为硅源,以NaOH为催化剂,合成出带有季铵荷正电基团的有序介孔材料(QAS)。采用XRD,TGA、BET、SEM,XPS、TEM、FT-IR等手段对产品结构进行了表征和分析。结果表明,产品具有较为均一的六方介孔结构,孔径约为3.5nm,产品中季铵荷电基团的含量约为1.41mmol/g。     

纳米CdS对聚丙烯膨胀型阻燃剂的协同效应

将单组分膨胀型阻燃剂新戊二醇磷酸酯三聚氰胺盐(NPM)和纳米硫化镉(CdS)加入聚丙烯中进行阻燃处理,应用氧指数和热重分析评价了该体系的阻燃性能和纳米CdS的阻燃协同效应,当纳米CdS加入量达到1.0 phr时,可以观察到明显的协同效果.采用红外光谱、扫描电镜和X射线衍射对纳米CdS协同机理进行了分析,结果表明,纳米CdS能促进炭层的生成,并通过催化和交联作用而影响炭层结构.     

Preparation and characterization of conducting polyaniline/silica nanosheet composites

A series of polyaniline/silica nanosheet composites (PANI/SNS) with different contents of the silica nanosheets derived from vermiculite via acid-leaching were prepared via the in situ chemical oxidation polymerization. The PANI/SNS composites were characterized with Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and electrical conductivity measurement. It is interesting that the electrical conductivities of the PANI/SNS composites increased with the increasing of the contents of the silica nanosheets added because of the moisture absorption. It was confirmed by the TGA analysis.     

Investigation of in vitro permeability and in vivo pharmacokinetic behavior of bare and functionalized MCM-41 and MCM-48 mesoporous silica nanoparticles: a burst and controlled drug release system for raloxifene

In the present work, MCM-41 and MCM-48 type of nanoparticles were successfully engineered. Effect of nanosize and amine functionalization on drug release, in vitro intestinal absorption and in vivo pharmacokinetic behavior was investigated in a comprehensive manner. The tailor-made bare and surface decorated MCM-41 and MCM-48 were synthesized and evaluated for their mesoporous skeleton, pore size, particle size, surface area, zeta potential, etc. by nitrogen sorption, DLS, TEM, etc. Incorporation of raloxifene (RLF) was affirmed using optimized immersion-solvent evaporation technique and its success confirmed by DSC, IR, and XRD analysis. TGA analysis revealed higher %grafting of amine groups on the exterior and larger RLF encapsulation into mesoporous derivate. The detailed in vitro release study revealed SGF to be the most compatible media for RLF showing an initial burst release from pristine nanoparticles and a delayed release from surface coated nanoparticles. Furthermore, release kinetics model data demonstrated Weibull and Higuchi as the best fit models for bare and amine-functionalized nanoparticles respectively. Moreover, an in vitro permeability study on Caco-2 cell line revealed higher absorption by engineered nanoparticle as compared to pure RLF and its marketed formulation. The supremacy in the in vivo pharmacokinetic parameters of RLF-41 and RLF-48 was demonstrated with 3.33 and 3.50 times enhancement in the bioavailability of RLF with respect to RLF suspension. To sum up, the results obtained were superior and promising for synthesized nanoparticles and more precisely for MCM-48 amongst them.     

表面活性剂辅助农药在锂皂石中的插层及其性能

利用两性表面活性剂十六烷基磺基甜菜碱(SB)的辅助作用实现了农药功夫菊酯(LCT)在锂皂石(LAP)中的插层。先用离子交换法将SB、十二烷基羧基甜菜碱(DCB)、十二烷基氧化胺(OA)和阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)分别插层LAP,然后用SB胶束将LCT引入层间,得到LCT/SB-LAP、LCT/DCB-SB-LAP、LCT/OA-SB-LAP和LCT/CTAB-SB-LAP复合材料。采用X射线衍射(XRD)、液体核磁共振(¹HNMR)、电感耦合等离子发射光谱(ICP-OES)、傅里叶变换红外光谱(FT-IR)、热重/差热分析(TGA/DTA)和扫描电镜(SEM)对复合材料进行了表征。结果表明,LCT/SB-LAP、LCT/DCB-SB-LAP、LCT/OA-SB-LAP和LCT/CTAB-SB-LAP的层间高度分别为3.61、3.13、3.13和3.41 nm;LCT伴随SB分子成功进入LAP层间。提出了LCT在LAP中的插层机理。对复合材料中LCT释放行为的研究结果表明,释放速率和累积释放量主要依赖表面活性剂类型及其在层间的排列方式。     

Synthesis and characterization of mesoporous Si-MCM-41 materials and their application as solid acid catalysts in some esterification reactions

Mesoporous MCM-41 has been synthesized by sol–gel method at room temperature possessing good thermal stability, high surface area as well as retention of surface area at high temperature. The MCM-41 neutral framework has been modified and put to practical use by incorporating Al³⁺ in the siliceous MCM-41 framework and supporting 12-TPA (12-tungstophosphoric acid) onto MCM-41 by process of anchoring and calcination to induce Brønsted acidity in MCM-41 to yield Al-MCM-41 and 12TPA-MCM-41, respectively. The synthesized materials have been characterized for elemental analysis by ICP-AES, XRD, SEM, TEM, EDX, FT–IR and TGA. Surface area has been determined by BET method and pore size and pore size distribution determined by BJH method. Surface acidity has been evaluated by NH₃-TPD method. The potential use of Al-MCM-41 and 12TPA-MCM-41 as solid acid catalysts has been explored and compared by studying esterification as a model reaction wherein monoesters such as ethyl acetate (EA), propyl acetate (PA), butyl acetate (BA) and benzyl acetate (BzA) have been synthesized, optimizing several parameters such as catalyst amount, reaction time, reaction temperature and mole ratio of reagents.     

Synthesis of silver-iron oxide nanocomposites by thermal decomposition

Silver-iron oxide nanocomposites were synthesized by an easy thermal decomposition method using iron acetyl acetonate and silver acetate as precursors and oleic acid (OA) and oleyl amine (OLA) as the capping agents in a single step. The composite samples were characterized by X-ray diffraction (XRD), infrared spectroscopy, thermal gravimetric analysis (TGA), UV-Visible spectroscopy, scanning electron microscopy (SEM), and magnetic measurements. Powder XRD and UV-Visible spectroscopy results indicate the presence of nanocrystalline silver in the composite and the FT-IR results coupled with TGA results indicate the presence of ligand molecules on surface of the nanocomposites. The FE-SEM images show that the nanocomposite particles are mainly spherical in shape while the energy dispersive X-ray analysis studies indicate the presence of iron and oxygen in the composites. From the magnetic measurements, the composites were found to be superparamagnetic with characteristic blocking temperatures indicating the presence of iron oxide nanoparticles in the nanocomposites.     

Compatibilizing effect of mesoporous fillers on the mechanical properties and morphology of polypropylene and polystyrene blend

Polypropylene(PP)/Polystyrene(PS) (PP/PS = 80/20) blend with different types of fillers were prepared by using melt method. Four different types of fillers, namely mesoporous MCM-41 (without template), nano-SiO₂, Polymethylmethacrylate (PMMA)/MCM-41 and PMMA/SiO₂ were considered. For PMMA/MCM-41 filler, the synthesis of the filler consisting of entrapped strand of PMMA within the pores of mesoporous MCM-41 (without template) was described. The mechanical properties of the blend determined as the nano-fillers contents and the different types of blend were found to vary with the different interface between fillers and the matrix. SEM revealed a good interaction between the matrix phases and PMMA/MCM-41 or MCM-41 (without template). The decreased T_g of PS implied that the good adhesion between PP and PS blend was obtained by adding PMMA/MCM-41 nano-filler.     

Organic modified mesoporous MCM-41 through solvothermal process as drug delivery system

MCM-41 materials modified by organic aminopropyl groups have been successfully prepared through solvothermal process and have been used as drug-controlled delivery system of aspirin. The results show that the releasing properties of this delivery system are affected by the amount of aminopropyl groups on the pore wall and the ordered structure of mesoporous materials. These materials were characterized by XRD, TG, FT-IR, TEM, UV and N₂ adsorption.     

A novel application of mesoporous silica material for extraction of pesticides

The mesoporous silica material MCM-41 was prepared by the sol-gel method and characterized using X-ray diffraction (XRD), N₂ adsorption-desorption and thermogravimetric analysis. The material was tested for extraction of trichlorfon, pyrimethanil, tetraconazole, thiabendazole, imazalil and tebuconazole from mango fruit, with analysis using gas chromatography-mass spectrometry (GC/MS). In experiments carried out in triplicate, at a 1.0 mg/kg concentration level, recoveries using the MCM-41 sorbent were in the range 73-103%. Comparison of MCM-41 with commercially available silica gel showed that MCM-41 was a similar extracting phase for the pesticides investigated with a significant cost advantage over this conventional material.