基于HPMCP包覆介孔SBA-15的pH敏感药物缓释系统

以肠溶性包衣材料羟丙甲纤维素邻苯二甲酸酯(HPMCP)为原料,在负载法莫替丁(Famo)的SBA-15药片表面包覆聚合物膜,成功制备了一种新型的pH敏感药物缓释系统, 并考察了此缓释系统在不同pH释放环境中的释放行为. 结果表明: 在模拟胃液中(SGF, pH=1.2),HPMCP能致密包覆在药片表面,从而明显延缓Famo的释放速度;而在模拟肠液中(SIF, pH=7.5),HPMCP能够迅速溶于缓释溶液中,因而对Famo释放速度的影响甚微. 因此,可以将这种新型智能药物缓释系统应用于肠道靶向给药.     

Synthesis, characterization and sustaining controlled release effect of mesoporous SBA-15/ramipril composite drug

A loading of ramipril in SBA-15 (Santa Barbara Amorphous) mesoporous material was studied. (SBA-15)-ramipril composite material was characterized by chemical analysis, infrared spectroscopy, powder X-ray diffraction, low temperature N₂ adsorption–desorption at 77 K characterization techniques. Ramipril drug release processes from SBA-15 host to simulated body fluid (SBF), simulated gastric juice (SGJ), simulated intestinal fluid (SIF) were monitored in a simulated way and actions of the sustained release of (SBA-15)-ramipril was studied. The results showed that the loading amount of ramipril drug in SBA-15 was 90.30 mg/g. The cumulative sustained release rate of ramipril composite drug in SBF achieved 99.7 % after 27 h. When the sustained release of composite drug in SGJ was 8 h, the maximum cumulative sustained release ratio achieved 54.9 %. When the sustained release of composite drug was 9 h in SIF, the maximum cumulative sustained release ratio achieved 34.9 %. The method described in this study is suitable for carrying ramipril drug on SBA-15, and a new carrier to load ramipril drug was found. Meanwhile, the efficacy of ramipril drug and time efficacy could be improved.     

高分散TiO_2/SBA-15的制备及光催化性能

提出了一种制备高分散TiO2/SBA-15光催化剂的新方法.以钛酸四正丁酯(TB)和羧基改性的SBA-15(COOH/SBA-15)为原料,利用COOH/SBA-15表面上高分散的羧基与TB的配合作用将TB锚定,经过溶剂热及焙烧处理制得TiO2/SBA-15光催化剂.采用粉末X射线衍射(XRD),N2吸脱附,傅里叶变换红外光谱(FT-IR),透射电镜(TEM)等对所得催化剂进行了表征.结果表明:所得TiO2/SBA-15光催化剂为高结晶度的锐钛矿晶型,TiO2均匀地分散在SBA-15表面,TiO2/SBA-15光催化剂保持较好的介孔特征结构,具有较大比表面积.以降解罗丹明B(RhB)为探针反应,考察了所得TiO2/SBA-15光催化剂的光催化性能.与后处理浸渍法制备的光催化剂相比,本文制备的TiO2/SBA-15光催化剂表现出了更加优越的光催化性能.     

Functionalized SBA-15 materials as carriers for controlled drug delivery: influence of surface properties on matrix-drug interactions

Mesoporous SBA-15 materials were functionalized with amine groups through postsynthesis and one-pot synthesis, and the resulting functionalized materials were investigated as matrixes for controlled drug delivery. The materials were characterized by FTIR, N(2) adsorption/desorption analysis, zeta potential measurement, XRD, XPS, and TEM. Ibuprofen (IBU) and bovine serum albumin (BSA) were selected as model drugs and loaded onto the unmodified and functionalized SBA-15. It was revealed that the adsorption capacities and release behaviors of these model drugs were highly dependent on the different surface properties of SBA-15 materials. The release rate of IBU from SBA-15 functionalized by postsynthesis is found to be effectively controlled as compared to that from pure SBA-15 and SBA-15 functionalized by one-pot synthesis due to the ionic interaction between carboxyl groups in IBU and amine groups on the surface of SBA-15. However, SBA-15 functionalized by one-pot synthesis is found to be more favorable for the adsorption and release of BSA due to the balance of electrostatic interaction and hydrophilic interaction between BSA and the functionalized SBA-15 matrix.     

Effect of amine functionalization of spherical MCM-41 and SBA-15 on controlled drug release

MCM-41 and SBA-15 silica materials with spherical morphology and different particle sizes were synthesized and modified by post-synthesis method with 3-aminopropyltriethoxysilane (APTES). A comparative study of the adsorption and release of a model drug, ibuprofen, were carried out. The modified and drug loaded mesoporous materials were characterized by XRD, TEM, N₂ physisorption, thermal analysis, elemental analysis and FT-IR spectroscopy. Surface modification with amino groups resulted in high degree of ibuprofen loading and slow rate of release for MCM-41, whereas it was the opposite for SBA-15. The adsorbed drug content and the delivery rate can be predetermined by the choice of mesoporous material with the appropriate structural characteristics and surface functionality.     

pH值响应性毒死蜱/铜席夫碱配合物改性SBA-15的制备及缓释性能

以3-氨丙基三乙氧基硅烷（APTES）、水杨醛和铜离子为改性剂,通过后嫁接法制得铜席夫碱配合物改性SBA-15（Cu-SBA-15）,并以毒死蜱为模型药物,制备了毒死蜱/铜席夫碱配合物改性SBA-15缓释体系。利用TEM、SEM、XRD、N₂吸附-脱附、TG、FTIR和XPS对SBA-15、氨基改性SBA-15（NH₂-SBA-15）、水杨醛希夫碱改性SBA-15（SA-SBA-15）的形貌、结构和Cu-SBA-15的配位情况进行了表征,考察了SBA-15在改性前后对毒死蜱的吸附量和缓释性能,并着重探究了毒死蜱/铜席夫碱配合物改性SBA-15载药体系在不同pH值下的释药行为。结果表明,APTES和水杨醛能够通过后嫁接法修饰于SBA-15,修饰后仍保持十分有序的孔道结构。SBA-15通过改性后,其对毒死蜱的吸附量由100 mg·g^-1增加至195 mg·g^-1,且其对药物的缓释性能也得到改善。毒死蜱/铜席夫碱配合物改性SBA-15缓释体系显示出明显的pH值响应性,pH=3时的释药速率大于pH=11时,而在中性条件下的缓释效果相对最好。载药体系的释药行为可用Riger-Peppas动力学模型来描述,其药物释放由Fick扩散控制。     

pH值响应性毒死蜱/铜席夫碱配合物改性SBA-15的制备及缓释性能

以3-氨丙基三乙氧基硅烷(APTES)、水杨醛和铜离子为改性剂,通过后嫁接法制得铜席夫碱配合物改性SBA-15(Cu-SBA-15),并以毒死蜱为模型药物,制备了毒死蜱/铜席夫碱配合物改性SBA-15缓释体系。利用TEM、SEM、XRD、N2吸附-脱附、TG、FTIR和XPS对SBA-15、氨基改性SBA-15(NH_2-SBA-15)、水杨醛希夫碱改性SBA-15(SA-SBA-15)的形貌、结构和Cu-SBA-15的配位情况进行了表征,考察了SBA-15在改性前后对毒死蜱的吸附量和缓释性能,并着重探究了毒死蜱/铜席夫碱配合物改性SBA-15载药体系在不同pH值下的释药行为。结果表明,APTES和水杨醛能够通过后嫁接法修饰于SBA-15,修饰后仍保持十分有序的孔道结构。SBA-15通过改性后,其对毒死蜱的吸附量由100 mg·g~(-1)增加至195 mg·g~(-1),且其对药物的缓释性能也得到改善。毒死蜱/铜席夫碱配合物改性SBA-15缓释体系显示出明显的pH值响应性,pH=3时的释药速率大于pH=11时,而在中性条件下的缓释效果相对最好。载药体系的释药行为可用Riger-Peppas动力学模型来描述,其药物释放由Fick扩散控制。     

Novel modified nanoporous silica for oral drug delivery: loading and release of clarithromycin

Nanoporous silica SBA-15 was prepared to evaluate its application as an oral drug delivery system. A series of surface-functionalized nanopore materials as efficient clarithromycin delivery carriers was investigated. An efficient pH-responsive carrier system was constructed by hydrogen bond interaction between carboxyl and hydroxyl groups in the clarithromycin and the amine group in modified SBA-15. HPLC analyses of clarithromycin were run on a C₁₈ column using a mobile phase comprised of potassium dihydrogen phosphate, acetonitrile and methanol (30:40:30, v/v/v). Active molecules such as clarithromycin could be stored and released from the pore voids of SBA-15 by changing the pH. The amount of clarithromycin stored in the pores of nanoporous silica based on TREN [tris(2-aminoethyl) amine]-modified SBA-15 rods was up to 46 ± 4.8 wt% at pH 8. In addition, when the pH was below 4, clarithromycin was steadily released from the pores of SBA-15 (up to 97 wt% in simulated gastric medium).     

Submicron particles of SBA-15 modified with MgO as carriers for controlled drug delivery

Submicron particles with modified surface were synthesized by a simple one-pot synthesis approach and used as drug carrier for controlled release. Due to the alkalinity of MgO species on the surface, the amount of a model drug, ibuprofen, adsorbed on the modified surface was increased as compared to pure silica SBA-15 although the surface area was decreased by the surface modification. FTIR investigation indicated that the adsorption state of ibuprofen on MgO modified SBA-15 was different from that on pure silica SBA-15 and pure crystal ibuprofen. The result obtained from in vitro release test exhibited that the surface modification greatly decreased the ibuprofen release rate. In first 6 h in vitro release test, only 63% of the adsorbed ibuprofen was released from the MgO/SBA-15 (Si/Mg=20). In contrast, the release of ibuprofen was complete in 1 h from the pure silica SBA-15 under the same release conditions. The surface modified with MgO created affinity with acidic ibuprofen molecules and retarded the release rate from the mesoporous matrix. In addition, the release rate of ibuprofen could be modulated by varying the content of MgO, and was found to decrease with increasing amount of MgO on surface of SBA-15 submicron particles.     

Co(Ⅲ)官能化SBA-15的制备、表征及其催化环己烯环氧化

通过环戊二烯基修饰的SBA-15(SBA-15-Cp)与马来酸酐的Diels-Alder反应及水解合成了邻二羧酸官能化的SBA-15,并将原位生成的Co(Ⅲ)络合物负载于其上制得Co(Ⅲ)官能化SBA-15样品SBA-15-Co(Ⅲ).傅里叶变换红外光谱、元素分析和X射线光电子能谱法结果证实羧酸官能团和Co(Ⅲ)成功地...     

Physical state of poorly water soluble therapeutic molecules loaded into SBA-15 ordered mesoporous silica carriers: a case study with itraconazole and ibuprofen

The ordered mesoporous silica material SBA-15 was loaded with the model drugs itraconazole and ibuprofen using three different procedures: (i) adsorption from solution, (ii) incipient wetness impregnation, and (iii) heating of a mixture of drug and SBA-15 powder. The location of the drug molecules in the SBA-15 particles and molecular interactions were investigated using nitrogen adsorption, TGA, DSC, DRS UV-vis, and XPS. The in vitro release of hydrophobic model drugs was evaluated in an aqueous environment simulating gastric fluid. The effectiveness of the loading method was found to be strongly compound dependent. Incipient wetness impregnation using a concentrated itraconazole solution in dichloromethane followed by solvent evaporation was most efficient for dispersing itraconazole in SBA-15. The itraconazole molecules were located on the mesopore walls and inside micropores of the mesopore walls. When SBA-15 was loaded by slurrying it in a diluted itraconazole solution from which the solvent was evaporated, the itraconazole molecules ended up in the mesopores that they plugged locally. At a loading of 30 wt %, itraconazole exhibited intermolecular interactions inside the mesopores revealed by UV spectroscopy and endothermic events traced with DSC. The physical mixing of itraconazole and SBA-15 powder followed by heating above the itraconazole melting temperature resulted in formulations in which glassy itraconazole particles were deposited externally on the SBA-15 particles. Loading with ibuprofen was successful with each of the three loading procedures. Ibuprofen preferably is positioned inside the micropores. In vitro release experiments showed fast release kinetics provided the drug molecules were evenly deposited over the mesoporous surface.     

Natural Triterpenoid‐ and Oligo(Ethylene Glycol)‐Pendant‐Containing Block and Random Copolymers: Aggregation and pH‐Controlled Release

In this research, a series of random and block amphiphilic copolymers of norbornene derivatives containing biocompatible natural triterpenoid and oligo(ethylene glycol) pendants were synthesized by ring‐opening metathesis polymerization. These copolymers were heat and pH responsive, and could self‐assemble into core–shell spherical micelles in aqueous solution. Their hydrodynamic diameters corresponded to pH values and monomer sequences. By evaluating the loading and release capacity of hydrophobic molecules, it was found that 1) the higher the content of the hydrophobic triterpenoid, the higher the loading capacity; 2) the release speed could be trigged by the pH because of the deprotonation of the carboxyl groups on the triterpenoid. Additionally, the copolymers exhibited low cytotoxicity toward L929 cells, which makes them potential nanocarrier candidates for controlled drug delivery.     

Synthesis of carboxyl-modified rod-like SBA-15 by rapid co-condensation

Carboxyl-modified SBA-15 rod-like mesoporous materials have been synthesized by a facile rapid co-condensation of tetraethylorthosilicate (TEOS) and 2-cyanoethyltriethoxysilane (CTES), followed by hydrolysis of cyanide groups in sulfuric acid. The concentration of carboxylic groups was varied by changing the silica source ratio of CTES/TEOS from 0.05 to 0.3. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the uniform ordered mesoporous structure and rod-like morphology of SBA-15 have been preserved even at the high concentration of carboxylic groups employed. Characterization by Fourier transformed infrared spectroscopy (FTIR), solid-state NMR investigation indicated that carboxylic groups have been successfully grafted onto the surface of SBA-15 through siloxane bonds [(O(3))SiCH(2)CH(2)COOH. The negative charges of the modified SBA-15 materials were enhanced by the presence of the carboxylic groups on the surface. The capacity of lysozyme adsorption of the modified SBA-15 materials were found to be significantly improved as compared with pure silica SBA-15. The maximum amount of lysozyme adsorption on carboxyl-modified was increased with the pH of solution increased from 5.5 to 9.0.     

In situ infrared study of SBA-15 functionalized with carboxylic groups incorporated by a co-condensation route

Two samples of SBA-15 mesoporous silica with a different content of carboxylic groups (-COOH) were prepared by a co-condensation route, using 4-(triethoxysilil)butyronitrile as the organosilane agent, then treating the samples with sulfuric acid, which removes the template and simultaneously hydrolyses the -CN to -COOH groups, as shown by IR spectroscopy. Both incorporation of organosilane agents and subsequent acid treatment do not affect the ordered SBA-15 structure. The proton-donor ability of carboxylic groups, as well their accessibility to reactants, has been studied in the IR by dosing ammonia, which forms reversibly COO- groups and NH4+ ions. The related equilibrium constants have been determined by elaboration of IR data. Outgassing the samples at progressively increasing temperatures destabilizes to an increasing extent the ammonium/carboxylate ion pair, because of the decrease in surface polarity brought about by dehydration: this decreases the related equilibrium constants. The amount of carboxylic groups undergoing reaction appears instead to be constant with dehydration, and to coincide with the whole population of COOH groups. Titration with alkali solutions yielded surface concentrations for the two samples of ca. 1.0 and 0.45 COOH/nm2. Proportionality between the surface concentrations and the intensities of the C=O IR band is observed: this suggests that COOH groups are noninteracting with each other and allows the computation of the related extinction molar coefficient.     

Synthesis and characterization of mesoporous SBA-15/propranolol hydrochloride for controlled drug release study

Propranolol hydrochloride was incorporated into SBA-15 mesoporous material host by impregnation method to obtain host-guest nanocomposite material (SBA-15)-propranolol hydrochloride. By spectrophotometry, the amount of propranolol hydrochloride assembly was determined to be 382.05?mg/g (drug/SBA-15). Powder X-ray diffraction test results indicated that during the process of incorporation the framework of the molecular sieve was not destroyed and the molecular sieve still remained its structure ordering. Fourier transform infrared spectra showed that the framework of the prepared host-guest material was remained in good condition. Low-temperature nitrogen adsorption-desorption at 77?K results showed that the surface area and the pore volume of (SBA-15)-propranolol hydrochloride host-guest material decreased compared to those of the host molecular sieve, indicating that propranolol hydrochloride guest molecules have partially occupied the channels of the molecular sieve. Transmission electron microscopy and scanning electron microscopy results indicated that two-dimensional hexagonal mesoporous pore channels of the molecular sieve were retained and (SBA-15)-propranolol hydrochloride composite material remained fibrous crystals and the average diameter of sample was 336?nm. It was discovered in drug release principle in the simulated body fluid that the effective release time of the drug reached 30?h and the maximum cumulative released amount of propranolol hydrochloride was 99.3?%. When drug release time arrived at 5?h in the simulated gastric juice, the maximum cumulative released amount was 51.2?%.When drug release time arrived at 9?h in the simulated intestinal fluid, the maximum cumulative released amount was 70.1?%. The drug sustained release results showed that SBA-15 is a well-controlled drug release carrier.     

TEPA在SBA-15(P)上的嫁接形态及其对CO2吸附性能的影响

通过控制浸渍方法和其过程将四乙烯五胺(TEPA)负载到SBA-15原粉上制备氨基功能化的CO2吸附材料TEPA/SBA-15(P).利用X射线衍射(XRD)、氮吸附、元素分析和傅里叶变换红外(FTIR)光谱等手段对各种吸附材料进行表征分析,并对其CO2吸附能力进行评价.结果表明:TEPA乙醇溶液的动态浸渍过程可以使有机胺高度均匀地负载到SBA-15(P)的孔道内,并形成有利于CO2吸脱附的键合形式.提出了TEPA在SBA-15(P)上的键合作用机制,一方面TEPA的端基氨(-NH2)与载体中的表面羟基(-OH)和醚键(C-O-C)形成氢键,提高了TEPA的分散度;另一方面,TEPA乙醇溶液的动态浸渍过程有效地避免了TEPA分子间或分子内氢键的形成,从而使有机胺TEPA氨基官能团具有较高的吸附容量.     

嫁接法制备Ni/SBA-15催化剂的催化氯苯加氢脱氯

SBA-15表面经嫁接方式引入氨基官能团,与Ni络合制备了SBA-15负载的Ni催化剂(Ni/SBA-15N)。同时,采用传统的浸渍法制备了具有相似Ni负载量的催化剂(Ni/SBA-15)。在负载量相近条件下,Ni/SBA-15N的Ni颗粒分散性均高于Ni/SBA-15。XRD和TPR结果表明,催化剂焙烧后,在氨化SBA-15表面,Ni以硅酸镍形式存在,而在SBA-15表面,Ni以NiO形式存在。Ni/SBA-15对氯苯催化加氢脱氯活性不随Ni负载量的变化而变化;而在Ni/SBA-15N中,Ni负载量增加,催化剂活性增加。     

co-Condensation Synthesis of Salicylaldimine Calcium Complex Containing Mesoporous Silica Nanoparticles as Carriers for Drug Release

A series of functional mesoporous silica nanoparticles（MSNs） was synthesized by a one-step simple synthesis approach involving co-condensation of tetraethoxysilane（TEOS） and salicylaldimine ligand（Sal-Si） in the presence of cetyltrimethylammonium chloride（CTAC） under basic conditions.The target MSNs with different sizes （50,100 and 200 nm,respectively） were obtained.Furthermore,the Ca^2＋ cations were also introduced into MSNs.The prepared nanoparticles were characterized by means of infrared（IR） spectra,thermogravimetric analysis（TGA）,inductively coupled plasma（ICP）,CHN elemental analysis,nitrogen adsorption-desorption,scanning electron microscope（SEM） and transmission electron microscope（TEM）.Ibuprofen（IBU） which contains carboxyl groups was selected as a model drug.The results of drug loading and release reveal that the loading capacities and release behaviors of the model drug are highly dependent on the Ca^2＋ cations in MSNs.The release of IBU from the MSNs functionalized by Ca^2＋ cations is found to be effectively controlled when compared to the release from the MSNs without the functionalization of Ca^2＋ cations,which is due to the ionic interaction between carboxyl groups in IBU and Ca^2＋ cations in MSNs.     

The Influence of Temperature and Drug Concentrations Prednisolone in NIPAAm Copolymer

Controlled delivery systems would be more beneficial and ideal if the drug could be delivered with respond to external environmental change. It could be used to overcome the shortcomings of conventional dosage forms. Therefore, the correct amount of drug would be released upon the stimulation of such a temperature and concentration change. The purpose of study is to investigate the influence of temperature and drug concentration from poly(2-hydroxyethyl methacrylate and N-isopropylacrylamide)/poly(HEMA-NIPAAm). The macroporous structure 5HEMA15NIPAAm was showed the most rapid responsiveness in swelling ratio, polymer volume fraction, swelling and deswelling kinetics. The high drug loading capacity was achieved at or below ambient temperature, whilst the release profile was revealed sustain release of conventional anti-inflammatory drug; prednisolone 21 hemisuccinate sodium salt. In general, drug loading capacity and drug diffusion kinetics are influence by the porosity of hydrogels, temperature, and drug concentration.     

Adsorption of benzene onto mesoporous silicates modified by titanium

Mesoporous molecular sieve SBA-15 modified by titanium has been utilized for removing organic pollutants, such as benzene, from air. Titanium was impregnated inside SBA-15 by wetness impregnation after synthesis of SBA-15 (impregnation method) or was doped into the SBA-15 framework by the direct addition of Ti precursor into the sol during synthesis (doping method). In the breakthrough curves for gas-phase benzene adsorption, Ti addition into SBA-15 resulted in the enhancement of benzene adsorption capacity, depending on Ti loading amounts. An increase in adsorption temperature remarkably reduced the benzene adsorption capacity, indicating that the interaction between benzene and the materials was weak.