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1.
N-羧烷基-6-O-壳聚糖硫酸酯的制备   总被引:2,自引:0,他引:2  
以铜离子为模板定向合成了6-O-壳聚糖硫酯酯,然后分别用乙醛酸和丙酮酸在其N-位形成席夫碱,再经NaCNBH3还原制备了N-羧甲基-6-O-壳聚糖硫酸酯和N-(2-甲基-羧甲基)-6-O-壳聚糖硫酸酯,对制得的各化合物分别采用氧瓶燃烧法测定了硫含量(S%),采用HPGPC法测定了重均相对分子质量和相对分子质量分布宽度,并对各化合物的红外光谱(IR)和^13C-NMR核磁共振图谱进行了分析。  相似文献   

2.
几种O-羧甲基壳聚糖硫酸酯的制备   总被引:5,自引:0,他引:5  
以甲壳质为原料制备了O-羧甲基壳聚糖,再经不同的硫酸酯化工艺分别制备了O-羧甲基-N-硫酸酯基壳聚糖(Ⅰ),O-羧甲基-O-硫酸酯基壳聚糖(Ⅱ),O-羧甲基-N,O-硫酸酯基壳聚糖(Ⅲ)等3种不同硫酸酯基取代位置的羧甲基壳聚糖衍生物,对各化合物分别采用氧瓶燃烧法测定了硫含量(S%),采用HPGPC法制定了重均相对分子质量和相对分子质量分布宽度。并对各化合物的红外光谱(IR)和^13C-NMR核磁共振图谱进行了分析。  相似文献   

3.
肝素及硫酸乙酸肝素(HS)在氨基葡聚精族中存在很大生物学差异。1肝素及HS的化学组成和细胞定位HS及肝素链常发软附干核蛋白中心的丝氨酸残基上。化学合成的肝素是D-葡糖酵酸呈1,4与,乙酸-D-氨基葡聚糖连接的二糖交替连接物。修改后的生物合成程序是:(1)N-乙酸-D-氨基葡聚糖脱乙酸化后,此氨基重新硫酸化;(2)D-葡糖醛酸C5差向异构化为L-艾杜糖醛酸;(3)主要在L-艾杜糖醛酸和D一氨基葡聚糖残基上的CZ及C6位氧一硫酸化2(4)在D一葡糖醛酸和D一氨基葡糖残基上的C。及C3位氧分别一硫酸化则是次要的。HS生物合成…  相似文献   

4.
一种低分子壳聚糖硫酸酯铝的制备   总被引:6,自引:2,他引:4  
本文采用正交试验设计方法对壳聚糖进行氧化降解,获得了一种低相对分子质量的水溶性壳聚糖,并在此基础上经硫酸化和盐交换制得了一种低相对分子质量壳聚糖硫酸酯式铝盐,壳聚糖氧化降解实验结果表明降解的最佳条件是温度为80度,过氧化氢浓度为5%,降解时间为1h,在此条件一产品收率可达52.68%,其粘均相对分子质量为3990,对制是的低相对分子质量壳聚糖硫酸酯铝进行了红外光谱分析和部分理化性质测定,经测定定样品中有机硫(S)含量为9.10%,铝(Al)含量为20.58%,样品制酸力为188.59mL.g^-1。  相似文献   

5.
在手性二价钌络合物(6)催化下经不对称转移氢化合成了左旋-(S)-1-(2-呋喃基)乙醇(8)。催化剂(6)由均三甲苯经Birch还原后,与三氯化钌反应转化成二聚均三甲苯二氯化钌(3),再与(1S,2S)-N-(对甲苯磺酰基)-二苯乙二胺(5)络合而得。  相似文献   

6.
目的:研究硫酸壳聚糖的体内抗肿瘤作用。方法:用高、低(200、100mg/kg)两个剂量的硫酸壳聚糖分别腹腔注射治疗肉瘤180(S180)小鼠和艾氏腹水癌(EAC)小鼠10d,然后测定其抑瘤率、重要器官的内脏指数和生命延长率,同时设生理盐水组(空白对照组)和氟尿嘧啶组(阳性对照组)进行比较。结果:硫酸壳聚糖高、低剂量组和氟尿嘧啶组的抑瘤率分别为38.67%、30.19%和43.27%,3组的生命延长率分别为65.38%、69.23%和54.93%。和生理盐水组、氟尿嘧啶组相比,硫酸壳聚糖高、低剂量组的S180小鼠的胸腺指数均有明显增加(P〈0.05)。结论:硫酸壳聚糖能有效抑制S180小鼠肿瘤的生长和延长EAC小鼠的生存时间,其作用机制可能与其提高机体的免疫力有关。  相似文献   

7.
κ-卡拉胶五糖的制备及结构研究   总被引:1,自引:0,他引:1  
本文以κ-卡拉胶(Kappaphycusstriarum)为原料,经盐酸水解,强阴离子交换高效液相色谱(SAX-HPLC)分离纯化,得到了1种卡拉胶五糖,该五糖的结构经各种核磁共振波谱技术(1H-NMR,13C-NMR,1H-1H-COSY,1H-13C-HMQC)以及电喷雾离子化质谱(ESI-MS)得到了确证,其结构为:β-D-4-O-硫酸半乳糖(1→4)-μ-D-3,6-内醚半乳糖-β-D-4-O硫酸半乳糖(1→4)-α-D-3,6-内醚半乳糖-β-D-4-O-硫酸半乳糖。  相似文献   

8.
目的观察水杨酸硫代脯氨酸镨三元配合物{[Pr(C7H5O3)2(C4H6NO2S)]•2H2O }对体外培养HL 60细胞生长代谢热动力学的影响。方法应用微量量热法绘制[Pr(C7H5O3)2(C4H6NO2S)]•2H2O作用时HL 60细胞生长代谢产热曲线,解析生长代谢速率常数(κ)、最大热输出功率(Pmax)、达峰时间(tmax)及配合物对细胞生长代谢的抑制率(I) 等热动力学参数,实验72 h应用显微观测法检查细胞凋亡情况。结果不同浓度[Pr(C7H5O3)2(C4H6NO2S)]•2H2O处理HL 60细胞后,细胞生长代谢受到不同程度抑制,并呈浓度依赖性;[Pr(C7H5O3)2(C4H6NO2S)]•2H2O达到4.0 μg•mL-1时,肿瘤细胞κ和Pmax明显减小,I明显增大。结论[Pr(C7H5O3)2(C4H6NO2S)]•2H2O影响HL 60细胞生长代谢,且具有剂量 效应关系,其有效作用浓度为4.0 μg•mL-1。  相似文献   

9.
合欢皮中一个新的三萜皂甙   总被引:2,自引:0,他引:2       下载免费PDF全文
邹坤  涂光忠等 《中国药学》2000,9(3):125-127
从合欢皮的乙醇提取物中用色谱法分离得到1个三糖链三萜皂甙(1),其21位侧链含有较为少见的木糖。经化学和波谱分析,将皂甙1的结构鉴定为3-O-[β-D-吡喃木糖基-(1→2)-β-D-吡喃呋糖基-(1→6)-β-D-吡喃葡萄糖基]-21-O-{(6S)-2-反式-2-羟甲基-6-甲基-6-O-[4-O-(6R)-2-反式-2,6-二甲基-6-O-β-D-吡喃木糖基)-2,7-辛二烯酰基]-β-D-吡喃鸡纳糖基]-2,7-辛二烯酰基}-金合欢酸-28-O-β-D-吡喃葡萄糖基-(1→3)-[α-L-呋喃阿拉伯糖基-(1→4)]-α-L-吡喃鼠李糖基-(1→2)-β-D-吡喃葡萄糖基酯,为一新化合物,命名为合欢皂甙J23(1)。  相似文献   

10.
吴迪  刘辉  浦金辉  张婧  邹萍  郭旦峰 《医药导报》2013,32(2):142-145
目的考察自制O 羧甲基壳聚糖(O CMC)的抑菌活性及其影响因素。方法以金黄色葡萄球菌、枯草芽孢杆菌、大肠埃希菌、铜绿假单胞菌为标准菌株,采用菌落计数法计算抑菌率,比较羧甲基不同取代位置、不同浓度、不同pH对O CMC抑菌效果的影响。结果O CMC抑菌作用强于N, O 羧甲基壳聚糖和N 羧甲基壳聚糖;O CMC的抑菌作用与浓度、pH和供试菌种类有关。在一定范围内,其抑菌效果随浓度增大而加强,随pH增加而减弱;O CMC对革兰阳性菌的抑制作用强于革兰阴性菌。结论该O CMC具有广谱抗菌活性。  相似文献   

11.
Terminal 1,6-anhydro-aminosugars (1,6-anAS) are typical structural moieties of enoxaparin, a low-molecular-weight heparin (LMWH) widely used for prevention and treatment of thrombotic disorders. In the enoxaparin manufacturing process, these modified amino sugars are formed during the β-eliminative cleavage of heparin. To investigate the effect of terminal anAS on antithrombin (AT) binding and on inhibition of factor Xa (FXa), two octasaccharides containing modified AT-binding pentasaccharide sequences were isolated from enoxaparin. The molecular conformation of the octasaccharides terminating with N-sulfo-1,6-anhydro-D-mannosamine and N-sulfo-1,6-anhydro-D-glucosamine, respectively, has been determined both in the absence and presence of AT by NMR experiments and docking simulations. Reduced overall contacts of the terminal anAS residues with the binding region of AT induce a decrease in affinity for AT as well as lower anti-FXa activity. The anti-FXa measured either in buffer or plasma milieu does not show any significant difference, suggesting that the inhibition of anti-FXa remains specific and biologically relevant.  相似文献   

12.
Floating (F) microcapsules containing melatonin (MT) were prepared by the ionic interaction of chitosan and a negatively charged surfactant, sodium dioctyl sulfosuccinate (DOS). The DOS/chitosan complex formation was confirmed employing infrared spectroscopy, differential scanning calorimetry (DSC), solubility and X-ray diffraction analysis. The characteristics of the F microcapsules generated compared with the conventional non-floating (NF) microspheres manufactured from chitosan and sodium tripolyphosphate (TPP) were also investigated. The effect of various factors (crosslinking time, DOS and chitosan concentrations, as well as drug/polymer ratio) on microcapsule properties were evaluated. The use of DOS solution in coagulation of chitosan produced well-formed microcapsules with round hollow core and 31.2-59.74% incorporation efficiencies. Chitosan concentration and drug/polymer ratio had a remarkable effect on drug entrapment in DOS/chitosan microcapsules. The dissolution profiles of most of microcapsules showed near zero order kinetics in simulated gastric fluid (S.G.F: pH 1.2). Moreover, release of the drug from these microcapsules was greatly retarded with release lasting for several hours (t(50%) (S.G.F.): 1.75-6.7 h, depending on processing factors), compared with NF microspheres where drug release was almost instant. Most of the hollow microcapsules developed tended to float over simulated biofluids for more than 12 h. Swelling studies conducted on various drug-free formulations, clearly indicated that DOS/chitosan microcapsules showed less swelling and no dissolution in S.G.F. for more than 3 days, whereas, TPP/chitosan microspheres were markedly swollen and lost their integrity in S.G.F. within 5 h. Therefore, data obtained suggest that the F hollow microcapsules produced would be an interesting gastroretentive controlled-release delivery system for drugs.  相似文献   

13.
羧甲基壳聚糖银的合成及抑菌实验的研究   总被引:22,自引:3,他引:19  
目的研究羧甲基壳聚糖银的合成方法及其对金黄色葡萄球菌、铜绿假单胞菌、大肠埃希菌、肺炎克雷伯菌和变形杆菌的抑菌作用。方法对壳聚糖经化学修饰后的衍生物进行红外吸收光谱分析。用稀释法和凹环法对烧伤常见的病原菌进行抑菌实验。结果修饰后的衍生物经红外图谱分析表明 ,壳聚糖已被氯乙酸所修饰。羧甲基壳聚糖银对浓度均为 10 4 CFU/ml的金黄色葡萄球菌、大肠埃希菌、铜绿假单胞菌的抑菌率分别为 88%、80 .2 %和 75 .3%。羧甲基壳聚糖银和AgNO3 对金黄色葡萄球菌、铜绿假单胞菌的最低抑菌浓度相同 ,对大肠埃希菌的最低抑菌浓度则前者低于后者。结论羧甲基壳聚糖银对烧伤感染常见致病菌有抑制作用 ,它可作为一种新型的预防、治疗烧伤感染的药物。  相似文献   

14.
Evaluation of chitosan salts as non-viral gene vectors in CHO-K1 cells   总被引:1,自引:0,他引:1  
The aim of this study was to investigate chitosan/DNA complexes formulated with various chitosan salts (CS) including chitosan hydrochloride (CHy), chitosan lactate (CLa), chitosan acetate (CAc), chitosan aspartate (CAs) and chitosan glutamate (CGl). They were assesed for their DNA complexing ability, transfection efficiency in CHO-K1 (Chinese hamster ovary) cells and their effect on cell viability. CHy, CLa, CAc, CAs and CGl, MW 45kDa formed a complex with pcDNA3-CMV-Luc at various N/P ratios. CGl/DNA complexes were formulated with various chitosan molecular weights (20, 45, 200 and 460kDa). The CS/DNA complexes were characterized by agarose gel electrophoresis and investigated for their transfection efficiency in CHO-K1 cells. The cytotoxicity of the complexes was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay in CHO-K1 cells. Gel electrophoresis illustrated that complete complexes formed at N/P ratios above 2 in all CS of MW 45kDa. The transfection efficiency of CS/DNA complexes was dependent on the salt form and MW of chitosan, and the N/P ratio of CS/DNA complexes. Of different CS, the maximum transfection efficiency was found in different N/P ratios. CHy/DNA, CLa/DNA, CAc/DNA, CAs/DNA and CGl/DNA complexes showed maximum transfection efficiencies at N/P ratios of 12, 12, 8, 6 and 6, respectively. Cytotoxicity results showed that all CS/DNA complexes had low cytotoxicity. This study suggests CS have the potential to be used as safe gene delivery vectors.  相似文献   

15.
In this study, the potential of lecithin/chitosan nanoparticles (NPs) as a mucoadhesive colloidal nanosystem for transmucosal delivery of melatonin was investigated. The size, zeta potential and melatonin loading of the lecithin/chitosan NPs were investigated as a function of lecithin type (Lipoid S45, S75 and S100) and chitosan content in the preparation. The NPs were characterised by mean diameter and zeta potential ranging between 121.6 and 347.5 nm, and 7.5 and 32.7 mV, respectively, and increasing with lecithin-negative charge and chitosan content in the preparation. Melatonin loadings were up to 7.1%. All NPs were characterised by prolonged release profiles with an initial burst (approximately 25%), followed by a slow release phase. Approximately 60–70% of melatonin was released in 4 h. The permeability of melatonin was investigated using Caco-2 cells as an in vitro model of the epithelial barrier. Melatonin permeability from an NP suspension prepared with Lipoid S45 lecithin and a lecithin-to-chitosan weight ratio (L/C) of 20:1 (sample C2) was significantly improved compared to the permeability of melatonin from the solution (P < 0.001) and from all other NPs investigated (P < 0.05). The results obtained by the cell viability studies (MTT and LDH leakage assays) showed that C2 NP suspension did not induce plasma membrane damage or decrease cell viability and could be safely applied to Caco-2 cells in the concentration range tested (<400 μg/ml).  相似文献   

16.
甲壳胺和卡拉胶在溶液中的反应及其复合物性质   总被引:8,自引:1,他引:7  
甲壳胺与卡拉胶在溶液中反应生成不溶于水的沉淀。红外光谱分析及相反离子含量测定证明,甲壳胺和卡拉胶分子间的联结是通过甲壳胺分子中的—NH_3~+与卡拉胶分子中的—SO_3~-通过静电相互作用来实现的。形成的聚电解质复合物N/S摩尔比在较宽的范围内依赖于反应混合溶液组成比,pH值及甲壳胺的脱乙酰度。不同条件下形成的复合物具有不同的形戊结构,当甲壳胺分子与卡拉胶分子上的电荷密度接近时,扫描电镜观察到复合物呈现纤维状结构。复合物不溶于二甲亚砚,CH_3COCH_3/KBr/H_2O(20:20:60wt)三元溶剂,在加热时溶于浓甲酸和稀盐酸,且随甲壳胺脱乙酰度增加复合物的溶解性下降。此外,复合物具有一定的抗凝血性。  相似文献   

17.
壳聚糖及其衍生物体外抗幽门螺杆菌作用及影响因素   总被引:5,自引:0,他引:5  
目的研究壳聚糖及其衍生物在体外对幽门螺杆菌(Hp)的抑菌作用及其影响因素。方法采用打孔法检测了不同浓度、pH值、脱乙酰度壳聚糖及羧甲基壳聚糖在体外对Hp的抑菌作用。结果①壳聚糖和羧甲基壳聚糖在体外对3株Hp标准菌株具有普遍的抑菌作用;②在pH 6~4范围内,随pH值降低,抗菌作用增强,差异有显著性(P<0.01),最佳pH值为4;③70%、88.5%脱乙酰度壳聚糖及羧甲基壳聚糖的抗Hp作用差异有显著性(P<0.01~0.05),抑菌强度依次为DD70壳聚糖、DD88.5壳聚糖和羧甲基壳聚糖;④在质量浓度为10 g.L-1~50 g.L-1范围内羧甲基壳聚糖抗Hp作用差异无显著性;在质量浓度为5 g.L-1~20 g.L-1范围内70%、88.5%脱乙酰度壳聚糖抗Hp作用差异也无显著性(P>0.05)。结论①壳聚糖和其衍生物对Hp有普遍的抑菌作用;②壳聚糖及其衍生物的抗Hp作用受多种因素影响,其中pH值对壳聚糖抗菌作用的影响最为明显,在pH值6~4范围内,壳聚糖的抗菌活性随着pH值的下降而增强;③壳聚糖的脱乙酰度、结构(化学修饰)及分子量也影响壳聚糖的抗菌活性,不同的细菌所要求的脱乙酰度、修饰基团和分子量有着明显的差异。  相似文献   

18.

Purpose

The aim of this research work was to explore the possibility of providing multifunctional oral insulin delivery system by conjugating several types of dipeptides on chitosan and trimethyl chitosan to be used as drug carriers.

Method

Conjugates of Glycyl-glycine and alanyl-alanine of chitosan and trimethyl chitosan (on primary alcohol group of polymer located on carbon 6) were synthesized and nanoparticles containing insulin were prepared for oral delivery. Preparation conditions of nanoparticles were optimized and their performance to enhance the permeability of insulin as well as cytotoxicity of nanoparticles in Caco-2 cell line was evaluated. To evaluate the efficacy of orally administered nanoparticles, nanoparticles with the most permeability enhancing ability were studied in male Wistar rats as animal model by measuring insulin and glucose Serum levels.

Result

Structural study of all the conjugates by infrared spectroscopy and nuclear magnetic resonance confirmed the successful formation of the conjugates with the desirable substitution degree. By optimizing preparation conditions, nanoparticles with expected size (157.3–197.7?nm), Zeta potential (24.35–34.37?mV), polydispersity index (0.365–0.512), entrapment efficiency (70.60–86.52%) and loading capacity (30.92–56.81%), proper morphology and desirable release pattern were obtained. Glycyl-glycine and alanyl-alanine conjugate nanoparticles of trimethyl chitosan showed 2.5–3.3 folds more effective insulin permeability in Caco-2 cell line than their chitosan counterparts. In animal model, oral administration of glycyl-glycine and alanyl-alanine conjugate nanoparticles of trimethyl chitosan demonstrated reasonable increase in Serum insulin level with relative bioavailability of 17.19% and 15.46% for glycyl-glycine and alanyl-alanine conjugate nanoparticles, respectively, and reduction in Serum glucose level compared with trimethyl chitosan nanoparticles (p?<?0.05).

Conclusion

It seems that glycyl-glycine and alanyl-alanine conjugate nanoparticles of trimethyl chitosan have met the aim of this research work and have been able to orally deliver insulin with more than one mechanism in animal model. Hence, they are promising candidates for further research studies.  相似文献   

19.
Production of amarogentin in root cultures of Swertia chirata   总被引:1,自引:0,他引:1  
Conventional and Agrobacterium rhizogenes-transformed root cultures were studied with respect to growth and amarogentin content following cultivation in various growth media. The fastest growth rate was observed using Nitsch medium. The best amarogentin content was obtained after cultivation in root culture (RC) medium for which the slowest growth rate was noticed. Addition of sucrose at 6% and 9% (w/v), respectively, also resulted in better growth rates and increased total but unaltered relative amarogentin content compared to 3% (w/v) sucrose. No change in amarogentin content was observed upon addition of elicitors, putative precursors of amarogentin biosynthesis, and plant growth hormones with the exception of salicylic acid and chitosan: at 100 mM salicylic acid a reduction and at 25 mg/L chitosan an increase of amarogentin were observed at significant levels. The cultivation of S. chirata roots in a 2-L stirred-tank bioreactor was successful only with a stainless-steel mesh fitted inside the culture vessel for immobilization of the roots. A 15-fold enhancement of amarogentin content in the medium was achieved by a root permeabilisation treatment using Tween 20 at 1.3% (v/v) final concentration in the bioreactor.  相似文献   

20.
To develop novel delivery system for tuberculosis (TB) subunit vaccine, biodegradable chitosan microspheres were prepared and used to deliver a fusion protein, Ag85B-MPT64(190-198)-Mtb8.4 (AMM for short), made from three Mycobacterium tuberculosis genes. AMM-loaded microspheres were first characterized for their morphology, size, zeta potential, loading efficiency, and in vitro release of AMM. C57BL/6 mice were immunized at weeks 1, 3 and 5 subcutaneously with AMM formulated in chitosan microspheres, in incomplete Freund's adjuvant (IFA), or in phosphate-buffered saline (PBS), respectively. Three weeks after the last immunization, humoral and cell-mediated immune responses were examined. It was shown that the microspheres bound AMM quite efficiently (loading efficiency: >99%). AMM-loaded chitosan microspheres were observed as aggregated shapes with the average particle size of 5.78+/-0.65 microm and zeta potential of 32.77+/-1.51 mV. In vitro release studies revealed that only small amount of antigen was released in 16 days. Following subcutaneous administration, splenocytes immunized with AMM in chitosan microspheres produced higher levels of IFN-gamma compared to administration of AMM in PBS upon stimulation with Ag85B and synthetic peptide MPT64(190-198). The levels of Ag85B-specific IgG (H+L), IgG1 and IgG2a in sera of mice immunized with AMM in chitosan microspheres were also higher than those with AMM in PBS. These results indicate that chitosan microspheres when used as a carrier for fusion protein AMM could elicit strong humoral and cell-mediated immune responses.  相似文献   

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