甲壳素及壳聚糖制备方法的改进

目的优化甲壳素及壳聚糖的制备方法。方法采用分步浸酸、浸碱法制备甲壳素及壳聚糖。结果蟹壳中甲壳素提取率为18.56%;壳聚糖脱乙酰度为91.25%,黏均分子量为8.29×105。结论分步法较一步法更能制备出高质量的甲壳素及壳聚糖。     

甲壳素制备工艺改进——天然甲壳素的提取

甲壳素制备工艺改进为统一常温进行,操作简便,产品相对收率提高5～10％,同时降低了能耗、机械要求强度、劳动保护条件和生产成本,并经热分析说明产品维持了甲壳素的天然特性,即分子中每结构单元含有1/2分子缔合水,是天然的甲壳素产品并有益于其脱乙酰化物──壳聚糖质量的提高。     

甲壳化学的研究进展与应用概况

本文对甲壳素化学的基本框架以及3种关键物质——甲壳素、壳聚糖和寡聚糖的研究与应用进展作一综述.主要内容包括甲壳素的来源及提取、甲壳素脱乙酰化制备壳聚糖、通过壳聚糖降解和改性两种途径制备水溶性壳聚糖以及壳寡糖在医药、食品、化妆品和农业领域的应用.     

壳聚糖人工泪液的制备及应用

壳聚糖人工泪液的制备及应用李平（兰州医学院第一附属医院兰州７３００００）王爱勤谭干祖（中国科学院兰州化学物理研究所）张建林（兰州市药品检验所）壳聚糖（Ｃｈｉｔｏｓａｎ）是甲壳素的主要衍生物，是甲壳素脱除乙酰基后的产物——脱乙酰甲壳素，具有良好的生物相...     

复方茵柏合剂壳聚糖澄清工艺研究

目的研究壳聚糖澄清法用于复方茵柏合剂的除杂效果以及制备工艺的可行性。方法以绿原酸为评价指标，通过正交设计优选澄清条件，与原制备工艺比较，并进行稳定性试验。结果壳聚糖澄清法所制备样品中绿原酸含量、薄层色谱鉴别与原工艺比较均无显著差异，且澄清度和稳定性均优于原工艺。结论壳聚糖澄清法具有简化工艺、缩短生产周期、提高制剂稳定性等优点，可用于复方茵柏合剂的制备。     

甲壳素及壳聚糖的医药应用

甲壳素是广泛存在于自然界的一种天然高分子材料，壳聚糖为其脱乙酰基衍生物。本文着重介绍甲壳素及壳聚糖在医药学上的应用。     

微波-EDTA脱钙技术在免疫组织化学染色中的应用研究

目的探讨微波(MW)—乙烯二胺四乙酸钠(EDTA)快速脱钙技术对骨及软组织抗原活性的影响。方法根据实验条件将待脱钙组织分为4组，即MW—EDTA(15℃)，Jenkins脱钙-固定液(20℃)，10％EDTA(20℃)和10％硝酸(20℃)，其中Mw—EDTA方法中EDTA的浓度分别是4％、7％、10％、13％和16％。应用免疫组织化学路AB染色，光镜观察免疫组织化学染色结果。结果MW—EDTA脱钙的免疫组织化学染色阳性细胞显著高于Jenkins脱钙—固定液(20℃)、10％ED—TA(20℃)及10％硝酸脱钙(20℃)3种脱钙方法，其时间明显缩短。其中用10％和13％浓度的EDTA脱钙的组织，其免疫组织化学染色阳性细胞又明显多于EDTA浓度为4％、7％和16％者。结论以Mw—10％EDTA技术进行组织脱钙，其脱钙时间短、免疫组织化学染色效果好。     

两种EDTA脱钙方法的比较

目的寻求切片制作更容易、染色效果更好的脱钙方法。方法对兔下颌骨分别使用15％EDTA微波脱钙法及15％EDTA低温脱钙法进行脱钙,从切片制作、免疫组化染色等方面进行比较。结果以15％EDTA低温脱钙法对兔下颌骨进行脱钙后,制作切片时脱片率明显降低,染色效果更好。结论以科学实验为目的对骨组织进行脱钙时,选用15％EDTA低温脱钙法能取得更准确的实验结果。     

壳聚糖及其衍生物在医药领域的应用研究进展

壳聚糖又称壳糖胺、几丁聚糖等，为天然多糖甲壳素（聚-1，4-β-N-乙酰-2-氨基-2-脱氧-D-葡萄糖）脱除部分乙酰基的产物。根据脱M乙酰度和溶解性的不同，一般将N-脱乙酰度〈55%不溶于1％乙酸（或1％盐酸）的称为甲壳素，将N-脱乙酰度〉55％可溶于1％乙酸（或1％盐酸）的产物称为壳聚糖。一般有实际应用价值的壳聚糖N-脱乙酰度都在70％以上。壳聚糖的相对分子质量虽因制备方法不同从数十万到数百万不等，     

壳聚糖用于镇咳宁口服液澄清工艺的研究

目的：探讨壳聚糖澄清法能否用于镇咳宁口服液的澄清工艺。方法：将壳聚糖用于镇咳宁口服液的澄清，并与部颁标准的制备方法比较，对盐酸麻黄碱、甘草次酸、桔梗进行定性，对盐酸麻黄碱进行含量测定，并作了稳定性实验比较。结果：壳聚糖澄清法能使药液澄清，能保留镇咳宁中的有效成分，采用HPLC法测定原工艺与本工艺生产的该制剂中盐酸麻黄碱含量，两基本一致。制剂的澄清度和稳定性均优于原工艺。结论：壳聚糖澄清法可用于镇咳宁口服液的澄清工艺。     

Novel microparticle drug delivery systems based on chitosan and Eudragit(®)RSPM to enhance diltiazem hydrochloride release property

The aim of this study was to enhance the release properties of diltiazem hydrochloride (diltiazem HCl) by using microparticle system. For this reason, microparticle drug delivery systems based on chitosan and Eudragit(?)RSPM were developed. The microparticles were prepared by using double-emulsion solvent extraction method and the mean sizes of microparticles were less than 120?μm. The in vitro drug release from microparticles was studied in simulated gastric (pH 1.2) and intestinal media (pH 7.4) than the results were evaluated by kinetically. In vitro diltiazem HCl release from microparticles showed good zero order kinetic. For the microparticles with chitosan, the release of diltiazem HCl at pH 1.2 could be effectively sustained, while the release of diltiazem HCl increased at pH 7.4 when compared to Eudragit(?)RSPM microparticles. The highest release percent obtained was 1:1 ratio of drug: polymer at pH 1.2 and 7.4. All results clearly suggest that the release properties of diltiazem HCl were improved by using microparticle systems especially which contain chitosan.     

Comparative study of protective effects of chitin,chitosan, and N-acetyl chitohexaose against Pseudomonas aeruginosa and Listeria monocytogenes infections in mice

We conducted a comparative study of the protective effects of chitin, chitosan, and N-acetyl chitohexaose (NACOS-6) against mice infected intravenously or intraperitoneally with Pseudomonas aeruginosa and Listeria monocytogenes. Mice pretreated with chitin, chitosan, and NACOS-6 showed resistance to intraperitoneal infections by both microbes. Only mice pretreated with chitin and chitosan showed resistance to intravenous infections by both microbes. The number, active oxygen generation, and myeloperoxidase activity of peritoneal exudate cells (PEC) in the chitin, chitosan, and NACOS-6-treated mice were greater than those of the untreated mice. Also, these PEC factors from mice pretreated with chitin and chitosan were greater than those from the NACOS-6-treated mice.     

几丁糖对成纤维细胞增殖及Ⅲ型前胶原信使核糖核酸表达的影响

目的 :研究几丁糖对成纤维细胞增殖及Ⅲ型前胶原mRNA表达的影响 ,阐明其抗纤维化的作用机制。方法 :用四唑盐 (MTT)比色法及RNA斑点杂交分别检测NIH /3T3细胞增殖及Ⅲ型前胶原mRNA的表达。结果 :几丁糖能明显抑制成纤维细胞增殖及Ⅲ型前胶原mRNA的表达 ,并呈剂量依赖性。结论 :几丁糖可通过抑制成纤维细胞增殖及Ⅲ型前胶原mRNA的表达而起到抗肝纤维化作用     

Novel microparticle drug delivery systems based on chitosan and Eudragit®RSPM to enhance diltiazem hydrochloride release property

The aim of this study was to enhance the release properties of diltiazem hydrochloride (diltiazem HCl) by using microparticle system. For this reason, microparticle drug delivery systems based on chitosan and Eudragit^®RSPM were developed. The microparticles were prepared by using double-emulsion solvent extraction method and the mean sizes of microparticles were less than 120?µm. The in vitro drug release from microparticles was studied in simulated gastric (pH 1.2) and intestinal media (pH 7.4) than the results were evaluated by kinetically. In vitro diltiazem HCl release from microparticles showed good zero order kinetic. For the microparticles with chitosan, the release of diltiazem HCl at pH 1.2 could be effectively sustained, while the release of diltiazem HCl increased at pH 7.4 when compared to Eudragit^®RSPM microparticles. The highest release percent obtained was 1:1 ratio of drug: polymer at pH 1.2 and 7.4. All results clearly suggest that the release properties of diltiazem HCl were improved by using microparticle systems especially which contain chitosan.     

Antioxidant activities of chitobiose and chitotriose

Chitooligosaccharides, the oligomers made up of beta-1,4-linked D-glucosamine, are obtained by partial hydrolysis of chitosan, a deacetylation product of chitin. The antioxidant activity of various chitooligosaccharides was tested in vitro with aminoguanidine, pyridoxamine, and Trolox as reference compounds. Hydroxylation of benzoate to salicylate by H2O2 in the presence of Cu(2+) was effectively inhibited by chitobiose, chitotriose, aminoguanidine, pyridoxamine, and Trolox (their IC(50) values=18, 80, 85, 10, and 95 microM, respectively), whereas glucosamine and N-acetylchito-oligosaccharides (di-N-acetylchitobiose and tri-N-acetylchitotriose) did not show any inhibitory activity. Chitobiose and chitotriose were more potent than the 3 reference compounds in scavenging hydroxyl radicals produced by photolysis of zinc oxide: IC(50) values of the 2 oligomers were 30 and 55 microM, respectively. Such a scavenging activity of these 2 chitooligomers was also shown by the use of another system, a mixture of Fe(3+)/EDTA/ascorbate/H2O2, for producing hydroxyl radicals. Only chitobiose and Trolox, of the 10 compounds tested, had the ability to scavenge superoxide radicals generated by a non-enzymatic system using phenazine methosulfate and NADH. Taken together with our unpublished observation that chitobiose and chitotriose are appreciably absorbed from the intestine of rats, the present results suggest that these 2 chitooligosaccharides would act as effective antioxidants in vivo when orally ingested.     

Enhanced dissolution rates of piroxicam from the ground mixtures with chitin or chitosan

To increase the dissolution rate of piroxicam, chitin and chitosan which are widely occurring biodegradable natural materials were used as drug carriers. The ground mixtures of piroxicam with chitin or chitosan were prepared by grinding in a ball mill. The dissolution rates of piroxicam from the ground mixtures were enhanced markedly than that from the physical mixtures or from intact piroxicam. The X-ray diffraction peaks disappeared in the ground mixture indicating the production of the amorphous form. The comparison of infrared spectra of the physical mixture and the ground minture showed an interaction such as association between the functional groups of piroxicam and chitin or chitosan in the molecular level. The weight losses in TGA curves showed all the same patterns. However, in the ground mixture by DTA curve, the endothermic peak due to the fusion of piroxicam was disappeared indicating the different thermal property.     

阿昔洛韦胃漂浮缓释片的制备及体外释放

目的制备阿昔洛韦胃漂浮缓释片,并通过紫外分光光度法考察其体外释放影响因素。方法以阿昔洛韦为模型药物,分别以壳聚糖、羟丙基甲基纤维素K15M(HPMC K15M)、Eudragit S100和碳酸钙为基质制备胃漂浮缓释片,用释放度测定法考察影响药物释放的因素。结果随着HPMC K15M用量增加,药物的释放显著减慢,碳酸钙用量增加,药物释放加快。结论制备的阿昔洛韦胃漂浮缓释片漂浮性良好,且能够达到缓释的目的。     

微生物来源的甲壳素和壳聚糖的研究

研究培养时间对菌丝体内壳聚糖及其它主要成分含量的影响及产物的收率。方法：培养 ４８ ｈ，菌丝体数量很快增长，菌丝体干重达到 １３ ｇ／Ｌ培养基。甲壳素和壳聚糖的分离包括：用 ２％氢氧化钠溶液在 ９０℃条件下除蛋白质２ｈ，再用１０％乙酸６０℃、２ｈ提取壳聚糖，然后在ｐＨ９．０条件下沉淀。结果：鲁氏毛霉经２ｄ培养，甲壳素和壳聚糖产率分别为菌丝体干重的８．８％和７．４％。结论：鲁氏毛霉菌丝体可作为用于医药、化妆品等的甲壳素和壳聚糖的来源。     

Poloxamer/Cyclodextrin/Chitosan-Based Thermoreversible Gel for Intranasal Delivery of Fexofenadine Hydrochloride

To enhance permeation and solubility of an intranasal delivery system of fexofenadine hydrochloride (FXD HCl), a new formulation using poloxamer 407 (P407)/hydroxypropyl-β-cyclodextrin (HP-β-CD)-based thermoreversible gels with chitosan, was developed. Prepared gels were characterized by gelation temperature, viscosity, viscoelasticity, and drug release profile. The in vitro permeation study was performed in primary human nasal epithelial cell monolayers cultured by air–liquid interface method. The addition of chitosan caused the slight elevation of gelation temperature and viscosity-enhancing effect. Viscosity enhancement by the incorporation of chitosan caused the retardation of drug release from P407 gels in in vitro release test. The in vitro permeation profile showed that the increase in chitosan content (0.1% and 0.3%, w/v) significantly enhanced the permeation of FXD HCl. After intranasal administration of P407/HP-β-CD–based thermoreversible gels containing 0.1% and 0.3% of chitosan in rabbits at 0.5 mg/kg dose, plasma concentrations of FXD HCl were significantly higher than those of nasal solutions (p < 0.05). In particular, the bioavailability of the optimized thermoreversible gel containing 0.3% chitosan was about 18-fold higher than that of the solution type. These results suggested the feasibility that thermosensitive gels could be used as an effective dosage form to enhance the nasal absorption of FXD HCl.