相溶解度法研究环糊精对纳他霉素的包合作用

目的:研究β-环糊精（β-CD）和羟丙基β-环糊精（HP-β-CD）对纳他霉素的增溶作用。方法:采用紫外分光光度测定纳他霉素含量,相溶解度法研究β-环糊精（β-CD）和羟丙基β-环糊精（HP-β-CD）对纳他霉素的包合作用、增溶作用及包合过程中热力学参数变化。结果:纳他霉素的溶解度随着β-环糊精浓度的增加而呈线性增加,相溶解度图呈AL型;纳他霉素的溶解度与羟丙基β-环糊精浓度在一定范围内呈线性,但随着羟丙基β-环糊精浓度的增加呈负向偏离型,相溶解度图呈AN型。纳他霉素与2种环糊精在包合过程中的吉布斯自由能变化（ΔG）、焓变（ΔH）均为负值,纳他霉素与β-CD在包合过程中的熵变（ΔS）为负值,而与HP-β-CD包合过程中的熵变（ΔS）为正值。结论:纳他霉素与2种环糊精增溶作用明显。      

相溶解度法研究环糊精对纳他霉素的包合作用

目的:研究β-环糊精(β-CD)和羟丙基β-环糊精(HP-β-CD)对纳他霉素的增溶作用。方法:采用紫外分光光度测定纳他霉素含量,相溶解度法研究β-环糊精(β-CD)和羟丙基β-环糊精(HP-β-CD)对纳他霉素的包合作用、增溶作用及包合过程中热力学参数变化。结果:纳他霉素的溶解度随着β-环糊精浓度的增加而呈线性增加,相溶解度图呈AL型;纳他霉素的溶解度与羟丙基β-环糊精浓度在一定范围内呈线性,但随着羟丙基β-环糊精浓度的增加呈负向偏离型,相溶解度图呈AN型。纳他霉素与2种环糊精在包合过程中的吉布斯自由能变化(ΔG)、焓变(ΔH)均为负值,纳他霉素与β-CD在包合过程中的熵变(ΔS)为负值,而与HP-β-CD包合过程中的熵变(ΔS)为正值。结论:纳他霉素与2种环糊精增溶作用明显。     

富马酸与三种环糊精在水溶液中包合作用的研究

本实验分别探讨了α-环糊精、β-环糊精、羟丙基-β-环糊精在水溶液中对富马酸的包合作用.实验采用紫外吸收光谱法和相溶解度法研究三种环糊精在水溶液中对富马酸的包合和增溶作用,以及包合过程中热力学参数的变化情况.结果表明,富马酸与三种环糊精在水溶液中均可自发形成了1:1(物质的量比)可溶性包合物,从而增加了其溶解度.同时,富马酸与三种环糊精在包合过程中的吉布斯自由能变化(△G)、焓变(△H)和熵变(△S)均为负值,所有过程均为焓驱动过程,且为放热过程(△H＜0)和熵减过程(△S＜0).     

叶黄素浸膏的环糊精包合作用研究

目的:研究环糊精包合对叶黄素浸膏性能的改进效果。方法:HSCCC及HPLC分析浸膏成分,紫外法测定表观包合常数,研磨法制备包合物,以溶解性及稳定性指标考察包合效果。结果:色谱分析表明,叶黄素浸膏为成分复杂的混合物;叶黄素浸膏与环糊精存在较强的包合作用,且混合环糊精优于单一环糊精;单一环糊精的包合改进效果各异,β-环糊精的增溶效果较差,但稳定性好于羟丙基-β-环糊精;混合环糊精包合的改进效果明显,尤以β-环糊精/羟丙基-β-环糊精9:1的混合包合性能效果最佳。结论:混合环糊精包合成分复杂的叶黄素浸膏可弥补单一环糊精的不足,包合物的溶解度和稳定性均能得到明显改善。      

羟丙基-β-环糊精与4-羟基查尔酮的包合作用研究

本研究为了系统研究羟丙基-β-环糊精与查尔酮的包合作用,采用相溶解度法测定了β-环糊精(β-CD)和羟丙基-β-环糊精(HP-β-CD)包合4-羟基查尔酮过程中的热力学参数,并运用红外(IR)、X-射线衍射(XRD)、热重及差示扫描量热联用(TG/DSC)等分析手段对该包合物的理化性质进行了系统研究。相溶解度实验表明HP-β-CD对4-羟基查尔酮的包合效果优于β-CD,而热力学分析发现4-羟基查尔酮和HP-β-CD的包合是一个自由能降低过程,反应具有自发性,其结合过程受疏水作用力驱动。红外和X-射线衍射分析表明4-羟基查尔酮与HP-β-CD包合后,其物相发生了重大改变,4-羟基查尔酮以无定形的状态完全分散在HP-β-CD中。热重及差示扫描量热联用分析发现通过与羟丙基-β-环糊精的包合,4-羟基查尔酮的热稳定性得到了显著提高。     

羟丙基-β-环糊精对百里香挥发油包合作用的研究

采用正交实验与综合评分相结合的方法优化水溶液搅拌法制备百里香挥发油-羟丙基-β-环糊精(HP-β-CD)包合物的工艺条件,运用傅立叶变换红外光谱(FT-IR)对包合物进行表征,并利用气相色谱-质谱联用(GC-MS)技术对比分析了包合前后百里香挥发油的化学成分.结果表明,水溶液搅拌法制备百里香挥发油HP-β-CD包合物的最佳工艺条件为:百里香挥发油与HP-β-CD的体积质量比为1:10(mL:g),包合温度30℃,搅拌时间2.5h,HP-β-CD的浓度5％,在此最佳工艺下,平均包合物得率与挥发油利用率分别为91.77％和81.94％,该工艺合理、稳定、可行,有效地提高了百里香挥发油的稳定性.FT-IR和GC-MS分析说明,百里香挥发油与HP-β-CD已经形成了包合物,包合前后百里香挥发油的主要化学成分基本相同,但挥发油中各组分的组成比例发生了一定程度的改变,包合对百里香挥发油的化学成分略有影响.     

羟丙基-β-环糊精对百里香挥发油包合作用的研究

采用正交实验与综合评分相结合的方法优化水溶液搅拌法制备百里香挥发油-羟丙基-β-环糊精（HP-β-CD）包合物的工艺条件,运用傅立叶变换红外光谱（FT-IR）对包合物进行表征,并利用气相色谱-质谱联用（GC-MS）技术对比分析了包合前后百里香挥发油的化学成分。结果表明,水溶液搅拌法制备百里香挥发油HP-β-CD包合物的最佳工艺条件为:百里香挥发油与HP-β-CD的体积质量比为1:10（mL:g）,包合温度30℃,搅拌时间2.5h,HP-β-CD的浓度5%,在此最佳工艺下,平均包合物得率与挥发油利用率分别为91.77%和81.94%,该工艺合理、稳定、可行,有效地提高了百里香挥发油的稳定性。FT-IR和GC-MS分析说明,百里香挥发油与HP-β-CD已经形成了包合物,包合前后百里香挥发油的主要化学成分基本相同,但挥发油中各组分的组成比例发生了一定程度的改变,包合对百里香挥发油的化学成分略有影响。      

喷雾干燥法制备水溶性白藜芦醇/HP-β-CD微胶囊

利用羟丙基-β-环糊精(HP-β-CD)改善Res的水溶性,优化了喷雾干燥法制备Res/HP-β-CD微胶囊的工艺,采用UV、IR和SEM对Res/HP-β-CD微胶囊进行结构表征。结果表明,Res/HP-β-CD微胶囊的优化制备工艺为wReswHP-β-CD15(g/g),搅拌温度30℃,进料流量2.1mL/min,进风温度140℃,载药量15.18%,溶解度12.75g/L。UV、IR和SEM结果表明,Res与HP-β-CD通过氢键、疏水作用力等作用力形成Res/HP-β-CD微胶囊,并且粒径减少,提高了Res的水溶性。     

羟丙基-β-环糊精在药剂学中的应用与研究

综述羟丙基-β-环糊精的特性、优势以及近年来在药剂学中的应用和研究进展。     

羟丙基-β-环糊精的合成与包络性能

以β-环糊精和环氧丙烷为原料,异丙醇为分散剂,80℃下合成了溶解性良好的羟丙基-β-环糊精穴HP-β-CD雪,确定了适宜的合成条件.产品取代度大于8,产率85%.试验了HP-β-CD包络反应的条件.测定了HP-β-CD的溶解度、包络性能及包络物的释放速率:25℃时在水中的溶解度≥65%穴质量分数雪;与香料DDHI能形成量比为3∶1的包络物,该包络物能溶于亲水纤维的熔融体中形成稳定、均一、透明的共熔体;HP-β-CD对客体分子有良好的缓释作用.     

Complexation of Metal Ions by Cyclodextrins

Organic ligand containing coordination metal ion complexes and the organometallic compounds in which the metal atoms are covalently bound can form regular inclusion complexes with cyclodextrins. Organic ligands for complexation of the metal ions may be also appropriate substituent groups of a chemically modified cyclodextrin. With non-derivatised cyclodextrins only so-called Outer Sphere Hydroxo-complexes are formed. Metallocenes, arenes, rotaxanes, rhodium- and platinum-complexes are the typical metal ion or atom containing guest molecules. These complexes can be utilised as catalysts, enzyme models, siderophores, colour and fluorescence enhancing reagents, drugs, etc.     

Starches in Semidilute Aqueous Solution

Nine starches from different plants were studied in the semidilute concentration regime. The amylose content varied between 0% (waxy starch) and 76%. The applied concentration range of 5 to 30% (w/v) corresponds to typical concentrations used for thickeners in food and non-food industries. With the exception of the amylose rich starches the maximum concentration was at least 4 times larger than the overlap concentration. Up to a certain concentration a common master curve was found for all starches but at high concentrations this master curve was superimposed by association and aggregation phenomena. The aggregation is promoted by the presence of amylose. The onset of aggregation is shifted to lower concentrations when the amylose content in the starches was high. The aggregation proceeds in time. It could be followed by dynamic light scattering and quantitatively be evaluated. The time dependent ageing of the solutions and the finally formed gels gave evidence for a liquid-solid phase separation that is kinetically hampered by the presence of the branched amylopectin.     

葡聚糖水溶液流变性研究

本实验研究了葡聚糖水溶液的流变性能,选取了五种不同分子量的葡聚糖,分别考查了分子量、溶液浓度、溶液温度等因素对葡聚糖水溶液流变性的影响。结果显示,多数葡聚糖水溶液表现出牛顿流体的特性,而当葡聚糖分子量为531000,溶液浓度为30%时,溶液则表现出假塑性流体的性质,黏度随着剪切速率的提高而降低。当葡聚糖浓度较低时(≤1%),水溶液均表现出一种特殊的流变性,即黏度随着剪切速率增加先降低后升高,本研究对出现这一现象的原因进行了分析。     

纤维素硫酸酯水溶液性质的研究

本文以α-纤维素为原料,ClSO_3H-DMF为酯化剂,采用多相硫酸酯化法制备纤维素硫酸酯(Cellulose Sulfate,CS)。通过元素分析确定了CS的硫酸酯基取代度为2.0左右,13C-NMR测试表明,CS的硫酸酯基取代模式是C-6完全硫酸酯基取代和C-2部分或完全取代。CS在去离子水中具有良好的溶解性。根据相近取代度的CS系列产物的分子量与特性粘度的关系,通过Mark-Houwink拟合,确定了CS的糖链在稀溶液中呈现一种较为紧密的构象。在浓溶液中,CS的动力粘度随浓度增加而增大;外加盐能够促进CS聚电解质的电荷排斥作用,导致其动力粘度增加;添加二价盐Ca~(2+)可产生CS糖链的络合,显著提高CS的动力粘度;溶液pH环境为影响CS动力粘度的主要因素之一,在中性条件下动力粘度最大,酸性或碱性环境都会使其动力粘度下降。     

Stability of Saturated Acyl L-Ascorbates in Aqueous Solution

ABSTRACT: The decomposition of decanoyl l-ascorbate was measured at 40 °C and at pH 2 to 9. The decrease in the ascorbate concentration at every pH value was well expressed by the Weibull model. The stability of the ascorbate was the highest at pH 3 and lower at a higher or lower pH. The increase in the concentration of decanoic acid, which was formed through the hydrolysis of the ester bond in the ascorbate, was measured at pH 3, 6, and 9. The hydrolysis could be ignored at a pH equal to or lower than 6, whereas it was significant at pH 9. The initial concentration of the ascorbate scarcely affected its decomposition at pH 5 and 40 °C. The decompositions of acyl ascorbates with acyl chain lengths of 6, 8, 10, and 12 were measured at pH 5 and at different temperatures. The temperature dependency of the rate constant for the decomposition of each ascorbate was analyzed by the Arrhenius equation, and it was shown that the enthalpy-entropy compensation held for the decomposition of the ascorbates.     

羟乙基纤维素水溶液的流变性能的研究

采用旋转粘度仪和流变仪初步研究了羟乙基纤维素（HEC）水溶液体系的流变性，讨论了HEC水溶液表观粘度及剪切粘度的影响因素，及其与HEC在水溶液中结构间的关系。结果表明：HEC水溶液的表观粘度随其浓度的变化符合Huggins经验公式；随着时间的增加，HEC分子在其水溶液中分子链松弛，使其表观粘度降低；HEC水溶液体系为剪切变稀的流体体系。在本实验范围内，随着溶液浓度的增加，HEC水溶液的剪切粘度增大。     

超声辅助离子液体/阴离子表面活性剂双水相萃取虎杖中的虎杖苷和白藜芦醇

将超声辅助离子液体/阴离子表面活性剂双水相萃取和高效液相色谱法相结合,建立一种简单、绿色、高效的分析方法用于检测虎杖中的虎杖苷和白藜芦醇。本研究以水溶性离子液体为萃取剂,以阴离子表面活性剂为成相盐,在超声的辅助作用下,目标分析物被萃取于离子液体中。实验结果表明,最佳提取条件为:以400μL 1-丁基-3-甲基咪唑四氟硼酸盐为萃取剂,0.16 g十二烷基苯磺酸钠为成相盐,样品溶液pH 7.0,超声时间20 min,超声功率160 W。各化合物在线性范围内都具有良好的线性关系(r0.9995),日内和日间精密度分别低于3.27%和6.31%,检出限和定量限分别为2.8~12.3和9.4~41.1 ng/mL,样品加标回收率在86.88~94.13%之间。本研究采用离子液体代替传统的有机溶剂作为萃取剂,集提取、分离和纯化于一体,具有操作简单、溶剂用量少、提取时间短等优点,可广泛应用于中药活性成分的提取与分析。     

Cyclodextrins in Biotechnology

Cyclodextrins and their derivatives enhance the solubility of complexed substrates in aqueous media, but do not damage the microbial cells or the enzymes. Therefore the enzymatic conversion of lipophylic substrates can be intensified (accelerated, or performed at higher substrate concentration). Examples are the hydrolysis of triglycerides or conversion of hydrocortisone to prednisolon. In presence of an appropriate CD-derivative (e. g. 2,6-dimethyl-β CD) the lipidlike inhibitor substances are complexed, therefore the propagation of Bordatella pertussis and the production of pertussis toxin increases up to 100-fold. The tolerable level of toxic compounds at biological detoxication of sewage of organic chemical industry can be elevated by admixing small amount of β-cyclodextrin to the system, because the complexed toxic substances do not kill the detoxicating microbes.     

Cyclodextrins in Pesticides

Many synthetic pesticides (herbicides, insecticides, fungicides, etc.) can be complexed with cyclodextrins. This “molecular encapsulation” frequently results in advantageous modifications of the properties of complexed substances.

• a) The hydrophilicity is strongly reduced, i. e. wettability, rate of dissolution and extent of solubility is enhanced, which generally results in enhanced bioavailability.
• b) Volatile, liquid, and gaseous substances, or substances of intolerable stink can be converted into microcrystalline, stable, well formulable substances.
• c) Incompatible substances can be mixed when at least one of the reacting components is complexed.
• d) The selectivity between herbivorous/non-herbivorous insects toxicity can be enhanced.
• e) CD-complexes are per se micronized substances, they are easily dispergable, no electric charging was observed.
• f) Long lasting effect can be ensured (e. g. in soil) because the complexed substances are released only on contacting with water.
• f) Cyclodextrins exert a direct auxin-like effect on plants therefore phytotoxic effect of pesticides can be reduced, etc.

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