聚电解质微胶囊的制备及其包埋释放行为

以高压静电法制备的壳聚糖微球为模板,与海藻酸钠层层自组装制备多层聚电解质膜,再以乙酸溶出壳聚糖微球制备出微胶囊.调节乙酸的浓度及溶出时间以控制核内壳聚糖的残留量,从而诱导负电性荧光素钠的沉积.微胶囊内部荧光素钠的浓度随着包埋时间的增加而呈线性地提高,当荧光素钠溶液的浓度为2 mg/l时其最终包埋的浓度达到10.2 mg/l.这种聚电解质微囊对于小分子负电荷荧光素钠的释放行为主要受其囊壁和内部模板结构的影响,盐离子浓度对荧光素钠释放行为的影响较小.     

微胶囊化脂肪酶型TTI的制备及其性能研究

针对脂肪酶在时间-温度指示剂的应用中存在热稳定性能差,温度、pH值对其活性影响较大等问题,采用离子凝胶技术制备脂肪酶微胶囊。应用单因素试验和正交试验相结合的方法,以海藻酸钠、壳聚糖、氯化钙浓度为变量,优化脂肪酶微胶囊的制备工艺,对原脂肪酶与脂肪酶微胶囊的热稳定性能、最适温度与pH值进行研究,采用红外光谱(FTIR)、扫描电镜(SEM)对脂肪酶微胶囊结构及形貌进行分析,并对脂肪酶微胶囊在时间-温度指示剂中的应用做出初步研究。得到了脂肪酶微胶囊最佳制备工艺条件为：海藻酸钠质量浓度30 g/L,壳聚糖质量浓度6 g/L,氯化钙浓度0.3 mol/L。脂肪酶微胶囊的热稳定性比原脂肪酶有明显提高。脂肪酶微胶囊制备工艺稳定、可靠,具有应用于时间-温度指示剂中的实用价值。     

壳聚糖结合脱氢乙酸钠涂膜对槟榔品质的影响

目的以槟榔为实验材料,基于气调贮藏(O2和CO2的体积分数均为4%)技术,探究壳聚糖结合脱氢乙酸钠涂膜对槟榔的保鲜效果。方法采用不同质量分数壳聚糖溶液(0,0.5%,1.0%,1.5%)结合质量浓度为50 mg/L的脱氢乙酸钠对槟榔进行涂膜,测定其在气调贮藏期间对槟榔感官品质、腐烂率、营养品质的影响。结果涂膜后的槟榔各项品质显著优于未涂膜槟榔。结论经壳聚糖(0.5%)/脱氢乙酸钠(50 mg/L)涂膜后的槟榔在贮藏期30 d内能保持良好的品质,能延缓果皮变黄。     

疏水改性海藻酸钠衍生物包埋丁香油的释放性

目的通过化学方法将月桂醇与海藻酸钠接枝共聚形成两亲共聚物,对丁香油进行包埋形成微胶囊,使其具有一定的缓释性和良好的抗菌效果。方法利用两亲共聚物包埋丁香油形成包合物,采用单因素实验法,以包埋率为指标,评价月桂醇与海藻酸的接枝率对包埋率的影响,并在此基础上评价接枝率对缓释性以及不同环境下的稳定性和抗菌性能。结果在一定范围内包埋率随着接枝率的增大而升高;丁香油微胶囊的挥发率为14.11%,远低于丁香油的挥发率61.25%;释放试验中,丁香油微胶囊的缓释性明显优于未改性海藻酸纳,丁香油微胶囊能稳定缓慢地释放抗菌成分,控制大肠杆菌的生长。结论月桂醇改性海藻酸钠包埋丁香油形成的微胶囊具有一定的缓释和抗菌性能,突破了丁香油因挥发性强而存在的应用限制。     

肉桂精油微囊化及其在果蔬保鲜中的应用

目的以壳聚糖、海藻酸钠为壁材,以肉桂精油为芯材,采用复凝聚法制备壳聚糖微胶囊,并将其应用于水果保鲜中。方法通过光学显微镜、扫描电子显微镜、傅里叶转化红外光谱等,确定微胶囊的最佳工艺参数、芯壁比及添加质量分数,并以芒果为实验对象,研究添加不同微胶囊质量分数的壳聚糖溶液对芒果保鲜效果的影响。结果当壳聚糖/海藻酸钠质量比为1∶2,氯化钙质量分数为1%,p H值为5,戊二醛质量分数为60%,交联时间为60 min,芯壁比为4∶1时,制备形成的壳聚糖微胶囊成球效果较好;微胶囊在壳聚糖溶液中的添加质量分数为4%时,以其涂膜的芒果保鲜效果最佳。结论肉桂精油经囊化后有效减少了气味、延缓了挥发,在果蔬保鲜中有较重要的现实研究意义。     

Design and characterization of calcium-free in-situ gel formulation based on sodium alginate and chitosan

The aim of this study was to prepare and evaluate calcium-free sustained release drug delivery systems, based on the in-situ gelation of oral suspensions containing chitosan, sodium alginate and Ranitidine as drug model. The combined effects of polymer concentrations and their interactions on the rheological characteristics of both gels and suspensions and, on the kinetics of drug release were evaluated by using a central composite face-centered design. Rheological analysis showed that suspensions were potentially stable, with a viscosity increased by 1000 times compared to that of water. In addition, the obtained gels were consistent; their storage modulus could reach values close to 50?kPa when alginate concentration was greater than 7.5?g/100?mL and chitosan was fixed to 0.5?g/100?mL. In these conditions gels should have a higher gastric residence time, in comparison to the standard gastric emptying time (～2?h). Evaluation of the in-vitro release kinetics of Ranitidine showed that the association of the lowest concentration of chitosan (0.5?g/100?mL) with higher alginate concentrations generates sustained release kinetics profiles. The time corresponding to 63% of release was found close to 1.5?h, in which case the process is governed by Fickian diffusion. Finally, calcium-free alginate-chitosan based on the in-situ gelation of suspensions is advantageous as a drug delivery system for sustained-release.     

Dispersion of chitosan on perlite for enhancement of copper(II) adsorption capacity

Chitosan coated perlite beads were prepared by drop-wise addition of slurry, made of chitosan dissolved in oxalic acid and perlite, to an alkaline bath (0.7 M NaOH). The beads that contained 32% chitosan enhanced the accessibility of OH and amine groups present in chitosan for adsorption of copper ions. The experiments using Cu(II) ions were carried out in the concentration range of 50-4100 mg/L (0.78-64.1 mmol/L). Adsorption capacity for Cu(II) was pH dependent and a maximum uptake of 104 mg/g of beads (325 mg/g of chitosan) was obtained at pH 4.5 when its equilibrium concentration in the solution was 812.5 mg/L at 298 K. The XPS and TEM data suggested that copper was mainly adsorbed as Cu(II) and was attached to amine groups. The adsorption data could be fitted to one-site Langmuir adsorption model. Anions in the solution had minimal effect on Cu(II) adsorption by chitosan coated perlite beads. EDTA was used effectively for the regeneration of the bed. The diffusion coefficient of Cu(II) onto chitosan coated beads was calculated from the breakthrough curve and was found to be 2.02 x 10(-8) cm(2)/s.     

聚天冬氨酸对铜、碳钢缓蚀性能的影响

采用失重法研究了pH=7.5的自来水中聚天冬氨酸和苯骈三唑、钼酸钠、硅酸钠复配时对铜和碳钢-铜复合体系的缓蚀效果,试验表明:单一聚天冬氨酸和钼酸钠的缓蚀效果随其浓度的增加而增加;单一苯骈三唑的缓蚀效果随其浓度的增加其缓蚀性也增加,当浓度达3 mg/L时,缓蚀效果最佳;单一硅酸钠的缓蚀效果随其浓度的增加其缓蚀性也增加,当浓度达200 mg/L时,缓蚀效果最佳;在缓蚀剂总浓度为50.5 mg/L时4种药剂复配,显示出较好的协同效应,其最佳配比为10 mg/L聚天冬氨酸 0.5 mg/L苯骈三唑 10 mg/L钼酸钠 30 mg/L硅酸钠.电化学动电位极化曲线测试结果表明复合水处理剂对阳极、阴极均有缓蚀作用.     

Preparation of embolic NEMs loading capecitabine

The nanoparticles-embedded microcapsules (NEMs) with smooth surface, good sphericity, excellent dispersivity and uniform particle size distribution were prepared by emulsification combined with electrospraying to extend the sustained release performance of the embolic microcapsules loading capecitabine (CAP). The sodium alginate and chitosan with good biocompatibility were used as the materials and CAP as a small-molecule model drug. The drug loading, encapsulation efficiency and drug release of CAP in the NEMs were investigated. The results showed that the drug-loading and encapsulation efficiency both increased with the increment of chitosan and CAP concentration. The maximum values of drug loading and encapsulation efficiency were 1.97 and 18.01 % respectively when initial CAP concentration was 5.0 g/L and chitosan molecular weight 100 kDa. The cumulative release rate of CAP released from the NEMs was lower than 30 % in 0.5 h, which indicated that there was no obvious initial burst release behavior. In the subsequent 240 h, the release results confirmed that the NEMs had better sustained release properties compared to pure microcapsules, and it might be a new anticancer drug delivery system in the future studies.     

Development of chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate as a buccal mucoadhesive patch to treat desquamative gingivitis

The aim of this research was to develop chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate as a buccal mucoadhesive patch to treat desquamative gingivitis, which was fabricated through an environmental friendly process. Mucoadhesive films increase the advantage of higher efficiency and drug localization in the affected region. In this research, mucoadhesive films, for the release of hydrocortisone sodium succinate, were prepared using different ratios of chitosan, gelatin and keratin. In the first step, chitosan and gelatin proportions were optimized after evaluating the mechanical properties, swelling capacity, water uptake, stability, and biodegradation of the films. Then, keratin was added at different percentages to the optimum composite of chitosan and gelatin together with the drug. The results of surface pH showed that none of the samples were harmful to the buccal cavity. FTIR analysis confirmed the influence of keratin on the structure of the composite. The presence of a higher amount of keratin in the composite films resulted in high mechanical, mucoadhesive properties and stability, low water uptake and biodegradation in phosphate buffer saline (pH?=?7.4) containing 10⁴?U/ml lysozyme. The release profile of the films ascertained that keratin is a rate controller in the release of the hydrocortisone sodium succinate. Finally, chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate can be employed in dental applications.     

高效液相色谱法测定罗汉果甜甙中甜蜜素

采用高效液相色谱法测定了罗汉果甜甙中的甜蜜素。将样品溶于水后,用Carrez试剂沉淀其中的杂质,离心,用次氯酸钠将样品溶液中的甜蜜素转化为N,N-二氯环己胺经正己烷萃取后测定。采用EclipseXDB-C18不锈钢柱分离,以乙腈-水(85+15)作流动相,二极管阵列检测器检测波长为314nm。结果显示,甜蜜素在样品溶液浓度为0.1mg/L~2mg/L范围内呈良好的线性关系,回收率为89.9%~94.7%,检出限为5mg/kg,测定结果的相对标准偏差小于5%。方法操作简便,结果准确可靠。     

壳聚糖复合保鲜膜制备及其拉伸性能研究

将充分溶胀的壳聚糖与三偏磷酸钠交联并与硅溶胶共混,制备出了壳聚糖复合保鲜膜,用万能拉力机测试了其拉伸性能。研究结果表明,交联和共混明显提高了壳聚糖复合保鲜膜的力学性能,并且壳聚糖浓度在1.2×10-4～1.4×10-4 mol/L,三偏磷酸钠的含量在0.08%,mSiO2∶m壳聚糖约为0.15时,保鲜膜综合力学性能最佳。     

壳聚糖包覆肉桂精油对葡萄保鲜的应用研究

以壳聚糖为壁材、肉桂精油为芯材,采用乳化-固化法制备了壳聚糖微胶囊,并将其应用于葡萄保鲜包装中。通过光学显微镜、扫描电子显微镜、傅里叶转化红外光谱仪等,确定了微胶囊的最佳工艺参数、芯壁比及添加质量分数,研究了添加不同微胶囊质量分数的壳聚糖溶液对葡萄保鲜效果的影响。结果表明:壳聚糖质量分数为1.5%,乳化剂添加质量分数为1.5%,油相与水相的体积比为5:1,交联剂添加体积为1.0 m L时,制备的壳聚糖微胶囊成球效果较好;壳聚糖包覆肉桂精油芯壁比为3:1,微胶囊在壳聚糖溶液中的添加质量分数为4%时,以其涂膜的葡萄保鲜效果最佳。     

壳聚糖/海藻酸盐微胶囊膜的物质扩散性能研究

针对微囊化细胞三维培养研究背景,以壳聚糖、海藻酸钠为微载体制备材料,采用脉冲电场液滴工艺制备海藻酸钙微球,使之与壳聚糖溶液通过聚电解质络合反应生成选择透过性微囊膜.以传统细胞培养的重要碳源葡萄糖与柠檬酸、氮源L-谷氨酸为小分子模型,以聚乙二醇为测定微囊膜截留相对分子质量的模型分子,开展微胶囊传递性能研究.结果表明,葡萄糖、柠檬酸和L-谷氨酸可以自由透过微囊膜扩散,并且柠檬酸和L-谷氨酸能通过竞争螯合Ca2+引起微囊凝胶结构解聚;采用20 mg/mL海藻酸钠溶液与5万相对分子质量、2 mg/mL壳聚糖溶液制备微胶囊,囊膜的截留相对分子质量为1 500.     

The impact of preparation parameters on typical attributes of chitosan-heparin nanohydrogels: particle size,loading efficiency,and drug release

Today, developing an optimized nanoparticle (NP) preparation procedure is of paramount importance in all nanoparticulate drug delivery researches, leading to expanding more operative and clinically validated nanomedicines. In this study, a one-at-a-time experimental approach was used for evaluating the effect of various preparation factors on size, loading, and drug release of hydrogel NPs prepared with ionotropic gelation between heparin and chitosan. The size, loading efficiency (LE) and drug release profile of the NPs were evaluated when the chitosan molecular weight, chitosan concentration, heparin addition time to chitosan solution, heparin concentration, pH value of chitosan solution, temperature, and mixing rate were changed separately while other factors were in optimum condition. The results displayed that size and LE are highly influenced by chitosan concentration, getting an optimum of 63?±?0.57 and 75.19?±?2.65, respectively, when chitosan concentration was 0.75?mg/ml. Besides, heparin addition time of 3?min leaded to 74.1?±?0.79 % LE with no sensible effect on size and release profile. In addition, pH 5.5 showed a minimum size of 63?±?1.87, maximum LE of 73.81?±?3.13 and the slowest drug release with 63.71?±?3.84 % during one week. Although LE was not affected by temperature, size and release reduced to 63?±?0 and 74.21?±?1.99% when temperature increased from 25°C to 55°C. Also, continuous increase of mixer rate from 500 to 3500?rpm resulted in constant enhancement of LE from 58.3?±?3.6 to 74.4?±?2.59 as well as remarkable decrease in size from 148?±?4.88 to 63?±?2.64.     

基于不同洗脱剂的单斜晶系钛基锂离子筛的制备及其吸附性能

采用高温固相法,以碳酸锂和二氧化钛为原料合成了锂离子筛前驱体,并分别考察了0.5mol/L盐酸和0.8mol/L过硫酸钠溶液对前驱体的洗脱及产物锂离子筛的吸锂过程。结果表明,0.5mol/L的盐酸作洗脱剂,循环洗脱-吸附5次后离子筛在含锂溶液(等体积0.01mol/L LiCl和0.01mol/L LiOH混合液)中的吸锂量稳定在18mg/g左右;0.8mol/L的过硫酸钠作洗脱剂,5次循环洗脱-吸附后对锂的吸附量约为16mg/g;吸锂过程适宜用伪二级动力学模型描述,且过硫酸钠的洗脱及所得离子筛的吸附动力学性能均优于盐酸作为洗脱剂的情况;过硫酸钠作洗脱剂有助于改善单斜晶系钛基锂离子筛的动力学性能。研究结果有助于拓宽锂离子筛的制备及应用。     

基于Eu-Ni-B稀土-复合电极电催化偏硼酸钠制备硼氢化钠的探索

为了获得低成本、高效率的制备硼氢化钠的技术。首先采用化学镀方法制备了Eu-Ni-B稀土-复合电极。以稀土-复合电极作为工作电极,对电催化偏硼酸钠制备硼氢化钠进行了探索。采用线性伏安法建立了硼氢化钠的检测体系,采用循环伏安法对电催化偏硼酸钠后的溶液进行检测。研究结果表明:以金电极对硼氢化钠进行检测及定量分析的方法可行,当电催化电位为-1.2 V、脉冲频率为TA=2 s、TC=2 s时,所制备的硼氢化钠达到了最大浓度1.63×10^-4 mol/L。随着电催化时间的不断增长,硼氢化钠的量呈现先增加后下降的趋势,当电解时间为2 h,硼氢化钠达到了最大浓度2.75×10^-4 mol/L,其可能的原因是随着电催化时间的增加,硼氢化钠的含量也会增加,但是硼氢化钠在非强碱体系中不稳定,也会随着时间的增加而逐步分解,故硼氢化钠的生成与硼氢化钠的分解形成竞争,当生成速度比分解速度慢时,随着时间的延长,溶液中的硼氢化钠含量自然会下降。     

Preparation and optimization of a novel microbead formulation to improve solubility and stability of curcumin

Curcumin is an active ingredient which is poorly water-soluble, leading to a low oral bioavailability. The aim of this research was to prepare a novel microbead formulation, and to solubilize, solidify, and improve storage stability of curcumin. Firstly, curcumin was solubilized with Kolliphor^TM RH40 and then microencapsulated by cross linking of sodium alginate with calcium chloride. A three-factor, three-level Box–Behnken design was employed to acquire the optimum microbead formulation, namely the best entrapment efficiency and in vitro curcumin release. The independent variables were sodium alginate concentration, calcium chloride concentration, and the weight of curcumin solution, while the dependent variables were entrapment efficiency and in vitro curcumin release. The optimized microbead formulation was 2.06% sodium alginate, 24.33% calcium chloride, and 1.28 g curcumin solution (containing curcumin and RH40 with a ratio of 1:22, g/g). Results showed that high concentrations of sodium alginate and calcium chloride could increase the entrapment efficiency. In vitro curcumin release decreased with increasing of sodium alginate as well as decreasing of calcium chloride. In conclusion, the optimum microbead formulation increased the solubility of curcumin and enhanced its stability, and achieved a high entrapment efficiency and in vitro curcumin release.     

多功能壳聚糖水凝胶医用材料的功能性研究

作为一类兼具应用价值和经济效益的新型功能高分子材料,水凝胶越来越受关注。以天然可降解的壳聚糖为载体,通过自由基接枝共聚法制备了壳聚糖水凝胶,重点研究了其吸附性及药物控释性能。结果表明:该水凝胶20d左右可以完全降解,降解性能良好。在25℃条件下,铜离子浓度为1200mg/L时,壳聚糖水凝胶对铜离子的平衡吸附量可达225.8mg/g。以亚甲基蓝为药物模型的控释实验结果表明,温度以及初始药物投加量对控释性能影响较大,48h累积释放率达70%左右,可在一定程度上实现缓释控释效果。     

丝素/海藻酸钠膜韧性的优化及膜释药机理分析

首先在丝素(SF)溶液中添加既定浓度的海藻酸钠(SA)溶液和一定体积的75%甘油、50%戊二醛以及模型药物罗丹明B(4g/L),将均匀混合液以浇铸方法制备丝素/海藻酸钠(SF/SA)膜模型药物缓释敷料;然后利用响应曲面法筛选最佳韧性(以断裂伸长率表示)SF/SA膜的制备参数;最后对优化膜的韧性和药物释放动力学模型进行检验与分析。实验得出,在浓度为2.5%的丝素溶液中,添加等体积0.96%浓度的海藻酸钠溶液,且甘油和戊二醛添加量分别为膜液总体积1.41%和4.47%时达到最优制备条件,此时膜的断裂伸长率为228.36%。检验结果显示相对对照组,优化组的断裂伸长率扩大了18.14倍;根据回归方程计算得出影响断裂伸长率的主效因素是甘油,且其与戊二醛具有显著协同作用。另外,根据优化组的释药结果分析表明:该体系具有药物缓释功效,释药动力学归属于Fickan模型。以上结果有利于丝素/海藻酸钠膜舒适型药物缓释敷料的制备,可为该生物材料的应用研究提供参考。