Chitosan and <Emphasis Type="Italic">β</Emphasis>-cyclodextrin microspheres as pulmonary sustained delivery systems

Chitosan and β-cyclodextrin were used to prepare microspheres with theophylline for pulmonary delivery by spray drying method. The characteristics, mucociliotoxicity, permeation rate and drug release were studied. The drug entrapments of microspheres Ⅰ, Ⅱ and Ⅲ were from 35.70% to 21.09% and 13.33%, while yields and encapsulation efficiencies were higher than 45% and about 90% respectively. The microspheres possessed low tap densities （0.34-0.48 g/cm^3）, appropriate diameters （3.35-3.94 μm） and theoretical aerodynamics diameters （2.20-3.04 μm）. SEM images showed the microspheres were spherical with smooth or wrinkled surface surfaces. FT-IR demonstrated theophylline had formed hydrogen bonds with chitosan and fl-cyclodextrin. The microspheres could effectively reduce the ciliotoxicity and easy to penetrate the memberine. The in vitro release of the microspheres was related to the ratio of drug/polymer and microspheres Ⅱ had a prolong release, providing the release of 72.00% in 12 h. The results suggestes that chitosan/β-cyclodextrin microspheres Ⅱ are a promising carrier as sustained release for pulmonary delivery.     

Preparation and Characterization in vitro of Sustained-release Captopril/Chitosan-gelatin Net-polymer Microspheres （Cap/CGNPMs）

The captopril/ Chitosan-gelatin net-polymer microspheres （ Gap/ CGNPMs ） were prepared using Chitosan （ CS ） and gelatin （ Gel ） by the methods of emulsification. A cross linked reagent alone or in combination with microcrystalline cellulose （ MCC ） was added in the process of preparation of microspheres to eliminate dose dumping and burst phenomenon of microspheres for the improvemeat of the therapeutic efficiency and the decrease of the side effects of captopril （ Cap ）. The results indicate that Cap/ CGNPMs have a spherical shape , smooth surface roorphology and integral inside structure and no adhesive phenomena and good roobility , and the size distribution is mairdy from 220 to 280 μm. Researches on the Cap release test in vitro demonstrate that Cap/ CGNPMs are of the role of retarding release of Cap compared with Cap ordinary tablets （COT）, embedding ratio （ER） , drug loading （ DL ）, and swelling ratio （ SR ）, and release behaviors of CGNPMS are influenced by process conditions of preparation such as experimental material ratio （EMR） , composition of cross linking reagents. Among these factors , the EMR（1/4）, CLR （ FOR ＋ TPP） and 0.75% microcrystulline cellulose （MCC） added to the microspheres are the optimal scheme to the preparation of Cap/CGNPMs. The Cap/CGNPMs have a good characteristic of sustained release of drug, and the process of emulsifieation and crossinking process is simple and stable. The CGNPMs is probable to be one of an ideal sustained release system for water-soluble drugs.     

Preparation and in vitro release properties of mercaptopurine drug-loaded magnetic microspheres

Magnetic Fe304 nanoparticles were synthesized by co-precipitation method and the mercaptopurine （MER） drug-loaded magnetic microspheres were obtained through emulsion cross-linking methods. The efficiency of this approach was evaluated in terms of drug loading content （DLC）, encapsulation efficiency （EE） and delivery properties in vitro, determined by high performance liquid chromatograph （HPLC）. The microspheres showed good DLC values of 11.8%, as well as good EE values of 79.4%. The in vitro drug release study was carried out in phosphate buffer solution （PBS） simulated body fluid, at 37 ~C with pH=7.4. The release profiles showed an initial fast release rate, which decreased as time progressed and about 84 % had been released after 48 h. The experimental results indicated that the prepared magnetic microspheres may be useful for potential applications of MER for magnetically targeted chemotherapy.     

Preparation of lung targeting microspheres of gelatin ceftiofur alkali

Gelatin ceftiofur alkali microsphere was prepared to observe its characteristics and evaluate preservation conditions. The glutaraldehyde was increased and the carboxylic methyl chitosan was added to improve the microsphere. The experimental results show microspheres have a better morphology surface and fairly regular structure with 4% glutaraldehyde. The average particle size is 15.84 μm and particle size distribution is narrow which shows a good uniformity. Microsphere size was affected by the stirrer speed, dosing ratio and curing degree. The greater drug loaded is, the better microspheres loading is; but with the increase of drug loading rate, the entrapment efficiency increases first and then decreases. The drug release rate of the microsphere is 24.90% in 0.5 h and 84.90% in 48 h, when CMC-GMs with 4% curing agent is 32.03% in 0.5 h and 88.44% in 48 h. So Gms embedding of ceftiofur alkali are better than CMC-GM. The stability tests show that strong light, high temperature, high humidity have a great influence on the microspheres.     

TiO_2纳米晶多孔微球的制备方法及形成机理

TiO2纳米晶多孔微球具有颗粒大、晶粒尺寸小及比表面积较高等优点.以明胶作为模板,以钛酸丁酯为原料,采用溶胶-凝胶法制备了TiO2纳米晶多孔微球,并采用透射电镜、X射线衍射仪对其性能进行了表征.实验结果表明:采用溶胶-凝胶法成功制备了纯锐钛矿型TiO2;明胶的加入对样品的物相组成没有影响,但改变了其晶粒尺寸和排布方式,得到了一种由纳米晶组成的多孔微球;微球直径约为200~500nm,其中孔隙约为2~5nm,平均晶粒尺寸为(14.3±0.9)nm.在此基础上对TiO2纳米晶多孔微球的形成机理进行了分析.     

Preparation and properties of gelatin-chitosan/montmorillonite drug-loaded microspheres

A kind of slow release drug-loaded microspheres were prepared with gelatin, chitosan and montmorillonite(MMT) by an emulsification/chemical cross-linking method using glutaraldehyde as cross-linking agent and acyclovir as model drug. The microspheres were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM), respectively. The morphology, drug content, encapsulation efficiency and drug-release behavior were investigated with different MMT content...     

Preparation of conducting poly N-methylaniline microsphere and its antibacterial performance to sulfate reducing bacteria

Microspheres of conducting polymers poly N-methylaniline （PNMA） were successfully synthesized through oxidation of N-methylaniline without any template. The average diameter of the microspheres with a smooth surface was about 0.40 μm when 0.2 M N-methylanUine was oxidized with 0.2 M ammonium persulfate in 0.2 M of HClO4 solution. The size of microspheres can be controlled by changing reaction time and temperature. The acid concentration was critical for the formation of microspheres with smooth surfaces. The excellent antibacterial performance of PNMA in novolac epoxy coating to sulfate reducing bacteria was demonstrated. Moreover, in API media, PNMA inhibited growth of SRB and then reduced the corrosion rate of carbon steel remarkably.     

双氯芬酸钠缓释微胶囊的制备与表征

以乙基纤维素为壁材,采用乳化-溶剂扩散技术制备双氯芬酸钠缓释微胶囊,通过考察包封率和载药量确定其制备工艺,并对微胶囊的形态和释放度等理化性能进行表征．结果表明,当有机相中乙基纤维素的质量浓度为3×10^-2g／mL,水相中乳化剂十二烷基硫酸钠的质量浓度为3×10^-3g／mL,双氯芬酸钠与乙基纤维素的投料比mEC：mDs为1：1,搅拌速度900r／min时制备出的微胶囊形态圆整,粒径范围6～24gm,药物包封率达25．12％,在人工肠液中可平稳缓释达8h．     

Preparation and evaluation in vitro of salicylic acid-pachyman nanoparticles

Pachyman based nanoparticles loading salicylic acid as model drug (SA-PNPs) were prepared by an inverse microemulsion crosslinking approach using epichlorohydrin (ECH) as crosslinker. The effects of crosslinking reaction time, initial volume ratio of oil to aqueous phase and dosage of crosslinker on the particle size of SA-PNPs were optimized by orthogonal experimental design. SA-PNPs prepared under the optimal conditions had the average size of 230 nm and high encapsulation efficiency of 90%. The in vitro drug release was also investigated and the release data were analyzed using zero order, first order and Higuchi’s kinetics model. According to the determined coefficients, release data fitted to Higuchi’s model, which suggested that the release of SA from SA-PNPs in phosphate buffer (pH 7.4) was diffusion controlled release. The experimental results indicated that pachyman possesses a promising potential to be applied as nanocarriers for controlled drug release.     

Preparation of Bauxite Ceramic Microsphere

Ceramic microspheres were prepared by using Chinese bauxite as raw materials through the centrifugal spray drying method. The control technology of microsphere size, degree of sphericity was researched. The ceramic microspheres were sintered by a double sintering process. The microstructure and composition of ceramic microsphere were investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and X-ray energy spectroscopy. The results show that the degree of sphericity of the ceramic microsphere was good and the particle size was 10-100 μm. The XRD analysis reveals that the main crystalline phase of the ceramic microsphere was a-Al2O3 and mullite （3Al2O3·2SiO2）. The product can be used as reinforced material for composite material, especially for antiskid and hard wearing aluminum alloy coating.     

Paclitaxel formulation with stable sustained-release behavior and its biological safety evaluation

Biological safety and stable sustained-release of the drug are two crucial issues involved in the formulation of paclitaxel.Focusing on these issues, by using the FDA approved polylactide as carrier material, soybean lecithin as surfactant and maltodextrin as thickener, paclitaxel loaded PLA microspheres were simply prepared by solvent evaporation, thus guaranteeing the biological safety. The introduction of maltodextrin as a thickener aided to a stable sustained-release of paclitaxel. Surface morphology, particle size, drug loading rate, encapsulation efficiency and in vitro drug release behavior were investigated.Biological safety evaluations such as acute toxicity, allergies, hemolysis, skin stimulation and genotoxicity test were also carried out. Results showed that the obtained microspheres were biocompatible and could release paclitaxel at a desirable constant rate.Therefore, the simply prepared paclitaxel formulation with good biological safety and desirable release behavior exhibited great potential of local injection of paclitaxel for the clinical use in the future.     

Chitosan Microparticles Intended for Anti：caries DNA Vaccine Mucosal Delivery： Synthesis, Characterization and Transfection

1Introduction Streptococcusmutans(S.mutans)hasbeenstrongly implicatedasacausativeorganismofdentalcaries[1].FusingtherationaltargetsproteinsofS.mutans,wecon structedanti cariesDNAvaccine.Comparedwithtradi tionalvaccines,DNAvaccineshaveobviousadvantages.Weh…     

抗癌药物羟基喜树碱纳米囊泡的研究

羟基喜树碱(Hydroxyeamptothecin,HCPT)是对多种癌症都有较好疗效的广谱抗癌药物,然而极低的脂水溶解性和不稳定性极大地限制了该药物的临床运用.合成了聚乙二醇化聚十六烷基氰基丙烯酸酯[poly(PEG cyanoacrylate-co-hexadecyl cyanoacrylate),PEG-PHDCA],并以此为载体材料,采用薄膜水化超声法制备HCPT的PEG-PHDCA纳米囊泡,并对其进行初步的理化性质和体内外释药特性的考察.制备得到的HCPT的PEG-PHDCA纳米囊泡平均粒径为(141.6±6.7)nm,平均ξ电位为(-18.2±2.2)mV,平均载药率为(2.92±0.21)%,平均包封率为(83.8±2.5)%.体内外释药实验表明:本实验制备的纳米囊泡制剂能有效延长释药时间,提高HCPT的稳定性、水溶性,是一种很有研究价值的剂型.     

Evaluation for the paleodose in thermoluminescence dating of porcelain

Sources, components and calibration of paleodose were studied for proper evaluation of the paleodose of porcelain in thermoluminescence (TL) dating. In the TL dating of porcelain using the pre-dose technique, the β dose from the internal natural radiation in the body of porcelain is the first, the environmental dose the second, and the α dose negligible. Sample thickness of 0.2–0.5 mm was used in the paleodose calibration. For a porcelain sample of such thickness, the distribution of β dose inside the sample was nonlinear when the sample (aluminium replaces porcelain in this experiment) was irradiated by a laboratory ⁹⁰Sr-⁹⁰Y β source. Therefore, the β dose used was only an average value. A distribution curve of β dose and the calculation of average β dose in the sample were obtained, according to the build-up and attenuation effects of β dose in the sample. The results showed that a sample thickness of 200 μm resulted in an average dose increment of about 4% compared to the surface whereas for a sample with a thickness of 400 μm, the average dose reduced by the same percentage, and that for a sample of 300 μm in thickness the average dose is equal to surface dose approximately. The average β dose in samples with various thickness can be obtained by the provided equations.     

The properties of solution precursor plasma spray nanostructured thermal barrier coatings

About 300 μm thickness uniform thermal barrier coatings (TBCs) were deposited on the 1Cr18Ni9Ti samples by solution precursor plasma spray (SPPS).The analysis methods,such as TEM,SEM,and XRD were used to characterize the coatings in the aspects of microstructure and phase compositions.The samples were quenched from 1121 ℃ to room temperature by forced-air to measure the thermal cycling capability.Coatings density were measured by means of water displacement.The experimental results show that grain size of the SPPS TBCs is about 30 nm with desired tetragonal phase ZrO2,and the SPPS TBCs(with 16% porosity) consist of arcuate pores,gelatin and melted particles.The hardness of the coatings is HR45Y38.5 and bond strength between coatings and substrates is 24.2 MPa.The thermal shock test show the coatings have a average life of 500 cycles which is about 2.5 times than that of conventional air plasma spray (APS) TBCs.     

Preparation and characterization of chitosan microsphere loading bovine serum albumin

To optimize the preparation process of chitosan microspheres and study its loading capacity, chitosan microsphere was prepared by crosslinking with glutaraldehyde, and bovine serum albumin (BSA) was absorbed onto chitosan microsphere. Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FITR), TA instruments and zeta potentiometer analyzer were used to characterize the parameters with respect to size, thermal characters, morphology, and zeta potential of the microspheres. The loading capability and in vitro release tests were carried out. The results showed that chitosan microsphere with particle size less than 10 μm and positively charged (+25.97±0.56 mV) can be obtained under the aldehyde group to amino group ratio at 1:1. A loading capacity of BSA at 28.63±0.15 g/100 g with corresponding loading efficiency at 72.01±1.44% was obtained for chitosan microsphere. In vitro test revealed a burst release followed by sustained-release profile.     

Design and preparation of bone tissue engineering scaffolds with porous controllable structure

A novel method of designing and preparing bone tissue engineering scaffolds with controllable porous structure of both macro channels and micro pores was proposed. The CAD software UG NX3.0 was used to design the macro channels’ shape, size and distribution. By integrating rapid prototyping and traditional porogen technique, the macro channels and micro pores were formed respectively. The size, shape and quantity of micro pores were controlled by porogen particulates. The sintered β-TCP porous scaffolds possessed connective macro channels of approximately 500 μm and micro pores of 200–400 μm. The porosity and connectivity of micro pores became higher with the increase of porogen ratio, while the mechanical properties weakened. The average porosity and compressive strength of β-TCP scaffolds prepared with porogen ratio of 60wt% were 78.12% and 0.2983 MPa, respectively. The cells’ adhesion ratio of scaffolds was 67.43%. The ALP activity, OCN content and cells micro morphology indicated that cells grew and proliferated well on the scaffolds. Funded by the Postdoctor Science Fund of China (No. 20070410715) and Shanghai Excellent Youth Special Fund (No. 17014)     

Chitosan andβ-cyclodextrin Microspheres as Pulmonary Sustained Delivery Systems

Chitosan and a-cyclodextrin were used to prepare microspheres with theophylline for pulmonary delivery by spray drying method.The characteristics,mucociliotoxicity,permeation rate and drug release were studied.The drug entrapments of microspheres Ⅰ,Ⅱ and Ⅲ were from 35.70%to 21.09% and 13.33%.while yields and encapsulation efficiencies were higher than 45%and about 90%respectively.with smooth or wrinkled surface surfaces.FT-IR demonstrated theophylline had formed hydrogen bonds with chitosan and a-cyclodextrin.The mierospheres could effectively reduce the ciliotoxicity and easy to penetrate the memberine.The in vitro release of the microspheres was related to the ratio of drug/polymer and microspheres Ⅱ had a prolong release,providing the release of 72.00%in 12 h.The results suggestes that chitosan/ a-cyclodextrin microspheres Ⅱ are a promising carrier as sustained release for pulmonary delivery.     

Characteristics and composition of particulate matter from coal-fired power plants

Measurements of the characteristics of particulate matter(PM)were performed at the inlet and outlet of the electrostatic precipitators(ESP)of four boilers in two full-scale pulverized coal power plants.PM was collected with a 13-stages low-pressure-impactor(LPI)having aerodynamic cut-off diameter ranging from 10.0 to 0.03μm for a size-segregated collection.The properties of PM including its con-centration,mass size distribution,emission characteristics,percent penetration of PM through ESP and elemental com...     

丹皮酚缓释微球的制备及体内外相关性研究

制备具有固体分散结构的丹皮酚缓释微球,并考察其体内外相关性。采用乳化溶剂扩散法制备丹皮酚缓释微球,考察微球的外观、载药量、包封率及体外释放行为。并以丹皮酚原料药为对照,根据大鼠的体内药物动力学试验结果,考察自制微球的体内外相关性。药物在37℃蒸馏水中12 h释放达到85%以上,大鼠体内的药动学实验表明,制得的丹皮酚缓释微球的体外释放累积百分数与体内吸收分数相关系数较好（r=0.977 5）,生物利用度是丹皮酚原料药的136.81%。该方法较适用于难溶性药物制备缓释微球。